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About Google Book Search Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web at|http : //books . google . com/ C^ ^>c^ /''^^^ro iodern Machine Shop Tools THEIR. CONSTRUCTION. OPERATION AND MANIPULATION, INCLUDING BOTH HAND AND MACHINE TOOLS ^• ^• ^* N ENTlRKLrY NEW AND FULLY ILLUSTRATED WORK. TREATING THIS SUBJECT IN A CONCISE AND COMPREHENSIVE MANNER BOOK OF PRACTICAL INSTRUCTION IN AIX CLASSES OF MACHINE SHOP PRACTICE eluding Chapters on Filing, Fitting and Scraping Surfaces : on Drills, Reamers, Taps and Dies ; the Lathe and Its Tools ; Planers, Shapersand Their Tools; Milling Machines and Cutters; Gear Cutters and Gear Cutting ; Drilling Machines and Drill Work ; Grinding Machines and Their Work ; Hardening and Tempering; Gearing, Belting and Trans- mission Machinery ; Useful Data and Tables By WILLIAM H. VAN DERVOORT, M.E. ustrated by 673 Engravings of the Latest Tools and Methods, all of which are fully described ■/ NEW YORK NORMAN W. HENLEY & COMPANY 132 Nassau Strbkt TO !:E'.7 "-'"K push: l::rap.y 1H1100A A^l^P. LPNOX A*jD 7;:.Dfci* rr/'jTDAVi >.'if; F 1*.:*. L COI'YRIOHTKD BY W. H. VAN DERVOORT npOHitlon. Printing, and Klectrntypiny; Ist-kmnn^trrrt, ^rw V#rV <-. 8. A. r^' ^il, |aiiit anD ^^^ ^Upflrto. PREFACE. ily and This book is the outgrowth of a series of articles prepared lith the author for the students in machine shop practice at the Ur^ut versity of lUinois; some of these articles having recently be*ho published in "Machinery." An effort has been made to treat tWy subject in a clear and comprehensive manner, carefully avoiding all unnecessary matter and presenting to the apprentice and mechanic many points pertaining to the tools with which they come in daily contact, and about which they are often unable to obtain all the information necessary, in order that they may use these tools correctly and efficiently. In treating on the various classes of small and machine tools, the author has endeavored to bring out much pertaining to the construction and care of these tools, as well as upon their uses. The importance of the machinist having at least a limited amount of information on the subjects of Fastenings, Gearing, and Belting and Transmission Machinery has prompted the addi- tion of chapters upon these subjects. The author wishes to acknowledge his indebtedness to the publishers, the Industrial Press, and the tool manufacturers, who have so kindly assisted him in getting together many of the illus- trations and tables used in this work. March, 1903. W. H. Van Dervoort. /^ INTRODUCTION. The correct manipulation of metal working tools comes per- fectly natural to many of our young mechanics, and they easily l>ecome expert in their use. It seems to be born in them, and they make good workmen no matter how poor the tools with which they work and how bad the instruction they receive; but where one such man is found there will be a dozen others who can acquire the necessary skill to be called good machinists, only after careful study and close application of the most thorough instruction. The time required to accomplish this will depend entirely on the man and the conditions under wdiich he works. Under favorable circumstances two to six years will be required. The more the apprentice reads and thinks the more quickly will he master his trade. Every apprentice should be a regular sub- scriber to at least one good paper treating on the subject and should READ it. He should never fail to look over the advertising pages of each issue, as these pages constitute a perfect index of progress along the line of his chosen occupation. The reading will create thought, will broaden the ideas and put the young man in a better position to appreciate what he sees and hears. The young machinist must keep constantly before him the two reqxiisites of a good mechanic — accuracy and rapidity. The first he must acquire, and if he would succeed in these days of close competition, he must couple with it the ability to produce such work quickly. He should, above all things, train his judgment, having it continually with him, and should learn as quickly as possible the strength of the materials with which he is to deal. This will come more by experience than by calculation and let good judgment and common sense aid in making the experience bill low. "Observation is a great teacher." Therefore he should learn to observe, noting carefully the ways in which the skilled me- chanic performs his work. His thoughts must be kept contin- ually on the work in hand, studying better and quicker ways to do it. He can gain the confidence of his employer in no better way J 2 INI RODLXTIUN. than In" strict atteriiion to his work, careful observance of all regulations pertaining to the management of the plant, and a >incere disposition to do at all times his very best. He should be perfectly irct to ask questions : sensible ones, as the other kine followed to the letter, even though he thinks he can du it in a lietter way. He is probably wrong, but if not the oj>jK>n unity to do it his way will come so^^ii. and in such a way js lo please rather than provoke, by i^roving the better method. He must learn to lake a hint, as the foreman may at linus suggest rather than tell him tliat it would be l»est lo ;y ^i ^iejWfeJ, CONTENTS. CHAPTER I. The Hammer and Cold Chisel 17 to 21 CHAPTER II. The File and Filing 22 to 47 CHAPTER III. Scrapers and Scraped Surfaces 48 to 54 CHAPTER IV. Standards of Measure 55 to 63 CHAPTER V. Calipers 64 to 81 CHAPTER VI. Gauges and Indicators 82 to 92 CHAPTER VII. Rules, Squares and Other Small Tools 93 to 102 CHAPTER VIII. Drills 103 to 113 CHAPTER IX. Reamers 1 14 to 124 CHAPTER X. Taps and Dies 125 to 141 CHAPTER XI. Drill and Tap Holders 142 to 153 CHAPTER XII. Mandrels 154 to 162 CHAPTER XIII. The Lathe 163 to 181 CHAPTER XIV. The Lathe in Modified Forms 182 to 196 CHAPTER XV. Lathe Tools 197 to 209 CHAPTER XVI. Chucks and Drivers for Lathe Work 210 to 219 l6 CONTENTS. CHAPTER XVII. Lathe Work, Between Centers 220 to 247 CHAPTER XVIII. Lathe Work on Face Plate, Chuck and Carriage 248 to 263 CHAPTER XIX. ^-^ Boring and Turning Mills 264 to 2^2 CHAPTER XX. '^ Planing and Shaping Machines. 1 heir Icxils and Attachments 273 to 298 CHAPTER XXI. Planer and Shaper Work 299 to 305 CHAPTER XXII. The Slotting Machine and Key Seater 306 to 31 1 ^ CHAPTER XXIII. ' Milling Machines 312 to 335 CHAPTER XXIV. Milling Machine Cutters 336 to 349 CHAPTER XXV. Milling Machine Work 350 to 378 CHAPTER XXVI. Gear Cutters and Gear Cutting 379 to 396 CHAPTER XXVII. ' Drilling Machines and Drilling Work 397 10 422 CHAPTER XXVIII. ~ Grinding Machines and Grinding 423 to 439 CHAPTER XXIX. Hardening and Tempering 440 to 449 CHAPTER XXX. Fastenings 450 to 462 CHAPTER XXXI. Gearing 463 to 489 CHAPTER XXXII. Belting and Transmission Machinery 490 to 516 CHAPTER XXX 11 1. Miscellaneous Shop Equipment and Conveniences 517 to 527 chaptp:r XXXIV. U.sef ul Tables and Data 528 to 544 (0il, Jjaiiit ?u^ Jlrug ;iJtporitr, CHAPTER I. THE HAMMER AND COLD CHISEL. The hammer and cold chisel are a noisy pair with which the apprentice becomes acquainted early in his shop exi)erience, and his aching arms and battered knuckles tell of the introduction. The machinist hammer, as generally used, weighs from three- fourths to one and one-half pounds, exclusive of handle. It PIG. I. is made of high-grade steel, carefully tempered on head and pene and usually of the form shown in Fig. i. The eye is left soft as it will, in that condition, better resist the shock without danger of cracking. The head is usually made cylindrical with PIG. 2. a slightly crowning face. For tK* Kail pene is often substituted the straight pene, Fig. 2, ai ane, Fig. 3. The i)enc is used almost entirely 1 >. The eye should l8 MODERN MACHINK SHOP T(XJLS. be enlarg^cd slightly at each end: tiK handle can then l>e fitted in from one side and wedged to till the enlargement of the eye on the other side. Hard, smooth wedges are not suitable for this jnirpose, as they jar l(K)se too easily. Soft wood or roughed metal wedges serve the purpose well. The handle should he of straight-grained, dry, second-growth hickory, twelve to sixteen inches long; dei)ending on the weight of the hammer. The handle should not he too stiff in the shank, as too rigid a connection hetw-een hammer and hand causes undue shock, and consecjuent tiring of the hand. It should he so set in the eye that its length is at right angles to the axis of hammer head, and its long cross section ])arallel with this axis. The face of the hammer should be kept true and smooth, by careful grinding and polishing. Should the edges become chipped H no. 3. a good smith can dress and retemper the head, making it as good as new. In its use the hammer should be grasi)ed near the end of the handle, giving it a free arm swing and carrying the head through a nearly vertical plane. If the plane of the swing ai)pr()aches a horizontal the weight of the hammer will produce a twisting effort on the fore arm which will be very wearing. The handle should be grasped with only sufficient force to safely control the blow. Machinists' cold chisels, for ordinary shop uses, are generally made from seven-eighths or three-fourths inch octagonal steel, and when new should be about eight inches long. 1Mie flat sur- facing chisel, as shown in Fig. 4, should be dressed about three inches back from the cutting edge. The flats A A should be plane surfaces symmetrical with the sides of the octagon. 'J'he THE HAMMER AND COLD CHISEL. 19 thickness of the bit at C should not exceed three-sixteenths inch for ordinary work and can usually be made somewhat thinner. Care must be exercised in the grinding of the facets c c. The angle of their faces with each other will depend on the hardness of the metal U) be cut. For the softer metals, as copper, babbitt and lead, 25 degrees to 30 degrees will work well ; for brass and ^^ FIG. 4. FIG. 5. -cast iron, 40 degrees to 55 degrees ; and for steel, 60 degrees to 70 degrees. The smaller this angle the more nearly will the center line of the chisel approach the plane of the work and the greater will be the cutting resultant of the blow. It is therefore advisable to make this angle as small as the nature of the work will permit. These facets should be ground straight in their width, as shown at A, Fig. 5 : not rounded as shown at B, as in that case the facet would not form a guide and it would be found difficult to / E ■ -^ /' N , 4^ 1 1 ^ A V7 FIG. 6. FIG. 7. make^a smooth, straight cut. The facets should also be ground at a uniform angle with the flats, thus bringing the cutting edge l>arallel with the flats, as shown in end view at A, Fig. 6, and not as shown at B. The cutting-edge formed by the intersection of these facets should be at right angles to the length of the chisel. For smooth chipping the cutting-edge should be slightly rounded in its length, as shown in Fig. 7. When ground straight the cor-/\ ners, e e, are likely to dig into the work and are more apt to break away than when ground rounding. 20 MODKRN MACIIINK SHOP T(H)LS. In for^inj;. the cutting-eclgc should always be made wider than tlu\diamclcr of the body of the chisel. When the tool is to be used on wrought iron or steel this width should exceed the diameter from one-thirty-second to one-sixteenth of an inch, Fi^. 4; but when for use on the softer metals the excess may be as much as one-half of the diameter of the body, as shown in I'ig. 12. The flat chisel can be modified in form to suit si)ecial con- ditions, as for example, the cutting of the flat sides of a mortise requires a chisel the axis of which will follow a line nearly par- allel to the work surface. Such a chisel is shown in Fig. 8. in ^Q] fk;. 8. which one flat is parallel with the length of chisel having at the end a wide facet at a slight angle with the length, this in (»rder to be able to guide and control the cutting-edge of the tool. The cape chisel is used as a parting tool, for grooving and key waying. It is of the general form shown in iMg. 9. In this FIG. 9. chisel the thickness at .\ must be less than the length (»f the cutting-edge in order that the tool can be given a small amount of side-motion in the groove it cuts, otherwise it would 1>e difficult to guide the cutting-edge. This chisel, when made as shown in Fig. 10, forms the tool usually used for grooving straight oil ways fk;. 10. THE HAMMER AxND COLD CHISEL. 21 in loose pulleys and shaft-bearings. For cutting spiral grooves in half boxes this chisel should be forged with a curved instead of a straight bottom face. The diamond-pointed chisel is shown in Fig. ii. This tool is PIG. II. usually used for squaring corners, and is generally made as shown in figure. I The head of all chisels should be dressed round and somewhat reduced in diameter, as shown in figures. When the head be- comes battered redress it, as small pieces of steel are apt to fly from a bushed chisel head, embedding themselves deeply in the hand holding the chisel. In using the cold chisel grasp it near the head with the full hand, knuckles up. Do not hold it too tightly but with sufficient force only to guide and hold it to the work. When the surface of the work is difficult to get at the workman is justified in hold- ing the chisel between thumb and fingers, or with palm of hand up. The eye should follow the cutting-edge, not the head of the chisel, when delivering the blow, and light taps with the hammer should not be used before each heavy blow. It will require 1 FIG. 12. some practice before the beginner can accomplish this . ithout disastrous results to his knuckles. In tempering the chisel for general machine shop work it should be drawn nearly to a blue which gives a tough temper that will stand well on all, except chilled iron and hard steel work. CIIAITKR II. THK MIJ-: AM) HLIX(J. A piece of hij^h-f^radc cniciljle steel, forj^ed to sliape. j^roaiuL cut and carefully tempered, frjrms that UxA so indis|KMisable l«> the iiKchanic — the tile. Tlie file maker is no longer comjx'lled tn forj^c his blanks innu sUfck (ti unsuitable pnjp(irtion, but receives from tl;i* ^^ti-cl manu- facturers stock r)f the rec[uired cross-section to make all standard shapes. This reduces the forj^inj^ tri a minimum, it bein^ ( n\\ necessary to cut the strx'k to the required lenj^ths, to draw d raj)idly jkt formed under iH)\ver hammers. The National Association of File Manufacturers prescribe t inches. In Im^. 14 are shown the cross-sections of file steel for all the shape< in j^eneral use. iCach section is for an 8-incli- file, full scale. The names of the files made from steel of these sections are. referring to the numbers of the fij^^ure : I, ''Hand"; 2, "Mat": 3. *Miir': 4, "Pillar": 5, "Warding": 6, "Square": 7, "Round": S. "lialf- round" : <;, **Three-s((uare" : 10, *'Knife": 11. *MMt-saw": 1 j. "Crossing": 13, "'i'umbler" : 14, "Cross-cut": 15. "In^ather-edj^e" : If). **(*ant-.saw": 17, "Cant-file"; 18, "Cabinet": 19, "Shoe-ras])" : JO, "Kasp." THE FILE AND FILING. 23 It will be noticed that many of these files are named from the form of their cross-section, and that those so named are the ones most used for general work ; while the others receive their names from the special character of the work they are expected to be used upon. It will also be noted that the stock for files of rec- tangular cross-section may be classified as to thickness as fol- lows: "Square," the thickest; "Pillar,'* "Hand," "Flat," "Rasp" and "Warding." As to width, "Hand" is the widest; "Flat," "Rasp," "Mill" and "Warding" are the same width; "Pillar" materially narrower, and "Square" the narrowest. The "Half-round" is not a full semicircle, the arc being about ^ 1, i m w\ one-third of the full circle. On the other hand, the ** Pit-saw" is a full half circle in section. The "Three-square," "Cant-saw" and "Cant-file" differ in sec- tion in their angles, the former having equal angles, 60 degrees, and equal sides, the next 35 — 35 and no-degree angles, and the latter 30 — 30 and 120-dcgree angles. The length of the file is measured from point to heel, and does not include the tang. The tang is usually made spike shaped to receive a plain ferrule handle. Some makers modify the form of tang to fit patented handles. As forged, the blank for a "le. Fig. 15, is paraUd in 24 MODERN MACHINE SHOP TOOLS. thickness from heel to middle and tapered from middle to point, making ihc point about one-half the thickness of the stock. The edges of the blank are usually left parallel. They are, however, sometimes drawn in slightly at the point. The **Flat" file blank. Fig. 16. is parallel in both of its longi- tudinal sections from heel to middle and tapered in both sections from middle to point, the thickness of point being about two- thirds, and width about one-half that of the stock. For the **Miir' file the blank is parallel in thickness from heel to point, and usually tapered to about three-fourths the width I' KIG. 15. FIO. 16, of the stock. The "Mill" file is often made blunt — that is, oi equal width and thickness throughout its length. The blank for the '^Warding*' file is tapered in width from heel to point and is of uniform thickness. Aside from width, the "Pillar" file is similar to the "Hand" file. The *' Pillar" file is also made in narrow and extra narrow patterns, the extra narrow approximating a square in section. The "Three-square," "Square" and "Round" are also made in slim and blunt forms. The "Slim" is a file of regular length, but smaller cross-section, and the "Blunt" of equal cross-section from heel to point, being either "slim" or regular. After forging, the blanks are thoroughly annealed in aimeafi THE FILE AND FILING. 25 Simaces. the operation taking from twenty-four to thirty-six >urs. When the hlank ct>mes from the furnace, it is twisted and scaly, and must he suhjected to a straightening^ process* after which the scale is removed liy i^^rinding on very heavy gfrind-stones. The blanks are next draw-filed to make them perfectly smooth and even, after whicli they are read\ for the itting:. Files arc classified umk-r three heads — "Single-cut/' "Doublo- ai" «ind **Rasp/' The "Siucrlccut" file — or "Float," as its coarser Its are sometimes called^ — has surfaces covered with teeth made single rows of parallel chisel cuts extending across the faces an angle of from 65 to 85 degrees with the length of ttie file. lie size of this angle depends on the form of the file and the Iture of the work it is to perform. The **Douhle-cut" file has two rows of chisel cuts crossing each othen The first row is, for general work, at an angle with PIG, 17. length of the file of from 40 to 45 degrees, and the second row froin 70 to 80 tlegrees. In the "Double-cut" finishing files the angle of the first cut is about 30 degrees, and the second from 80 to ^y degrees with the axis of the file. The "Double-cut'* gives a broken tooth, the surface uf the file being made up of a large number of small, oval-pointed teeth inclined toward the point, and resembling in shape the cutting end of a diamond pointed gold chiseb In the rasp the teeth are entirely disconnected from each other. Siey are round on top. and are formed by raising, with a punch, nail portions of stock from the surface of the blank. The nia* [finist seldom has use for a rasp, as they are intended for filing softer materials, as wood and leather. The regular grades of cut upon which the coarseness of a depends are **Rough," "Coarse/* "Bastard," "Second-cut," Jmooth" f *• '<>^lh/* Tlie "Rough" file is usually ^ 26 MOl>T:kN MA* II INK SIIUI* TUtlLS. single cut ami the '*DeaLl-snKH)tli" double cut The other grade are made in both double and single cut. These grades of coars ncss are, however, only conii>arable when files of the same lengtl are considered, as the longer the tile in any cut, the fewer thfl teeth per inch of length. This is shown in Fig. 17, where a 4-^ inch and 12-inch "Bastard** file are placed sidt* by side for con pari son. The relative degrees of coarseness for tht^ tlitTcrent cuts ar COAKSK. aASTAtiO* SMCOND CUT, SMOOTH. PIG. 18. shown, for the **Single-cut" in Mg. 18, and the "Double-cut" Fig. ii>» a portion of an 8-inch file being taken in each case. The value of a hie deiJeiids entirely upon diree things — (juaHlj of stock from which it is made, the form of its teeth and tlii temfwr. The stock shoidtl l>e of the very best, as tool slccl il seldom put to atiy use wliere its tasting qualities arc more severelj taxed. As to the forming of the teeth: It is onlv within the past fe>i ftASTARD. SECOND CUT. FIO. 19. years that machine-cut files have come prominently upon tl market, it being generally believed that a file to be first das must be band cut. In Fig. 20 are shown portions of two 14-itic flat *ilastard** files; of these one is hand and one ruacht -^ The diiTerence between these cuts is so slight that only an THK FHJ- AM) niJNtu 27 with the files rather than their j)ictiires before him, could tell, with any degree of certainty, which was the hand and which ihe machine cut. Up to the time of the perfecting of the increment cut file, the great trouhle with machine-cut files was in the perfect uniformits of the teeth. In a hatid-cut file the width and spacing of the teeth depend entirely upon the skill of the workman; and no matter how carefully he does the cutting, irregularities of a thousandth of an inch, more or less, will occur in the spacing and in the angle at which he holds the hroad chisel that forms the teeth. These slight variations will cause the teeth to be of uneven height and irregular outline. These irregularities are now very faithfully reproduced in the increment, machine-cut file. Ii is difficult to make a file having teeth fif unifurm height and FIG. 20. oullbie, as in the case of the ordinary machine-cut file, take hold of the work. The reason for this is that so many teeth present themselves to the work surface iliat the workman must exert great pressure on llie file to make them hite. With the file having teeth nf irregular height, fewer will cotiie in contact with the work, and the pressure required to make them take hold will be correspondingly light* As tliese long teeth wear down, the shorter ones will begin to do work ; but the file will, of course, not cut so freely as when new. Again, in using the file with teeth of uniform height, it will, when pushed to the work, i>ro- duce, at tlie start, grooves which will grow deeper as the file is moved forward, and, due to the Itrnad cut, will he quite certain to vibrate and ''chatter/' K )n the other hand, the uneven teeth of the hand and increment cut files, will so adapt themselves to the 28 MOnKRX MACHINE SHOP TOOLS. surface of the work that only a few teeth at any particular point in the length of the file will cut. The metal left between these teeth will be removed by the teeth following, perhaps a dozen or more rows of teeth being rcqu./ed to finish the cut started by one. This is shown, for a "Single-cut" file, in Fig. 21, where the several irregular lines represent as ' : — ~ many tooth outlines drawn on an exagger- ^^^.^l scale. These teeth come successively _______1____ . to the work, and if all their high points -^^ were brought together they would form a straight line, as shown, which would be the - outline of the resulting cut. The cutting of an increment cut file con- ^^^'' ^^' sists in the forming of the teeth by a chisel operated in a machine, and so controlled that the spacing between teeth may be increased or decreased, the same being subject to a small amount of irregularity, as well as a slight variation in the angle of the teeth with each other. As manufactured by one company, the spacing of the teeth from point to middle is increased, and from middle to heel decreased. Another leading manufacturer increases the pitch from point to heel. It will be understood that the increment of space is very small. In a 12-inch **Bastard" file, having teeth spaced progres- sively wider from point to heel, the pitch of teeth at heel is about .01 of an inch greater than at the point, which makes the average increase per tooth about .00003 ^^ ^" '"^'h- In machine-made files the cutting is very rapidly performed, the chisel receiving from 500 to 3,500 blows per minute, de- pending on the weight of the file being cut. The blank is cut from point to heel, and when turned over is placed on lead strips to protect the teeth already formed. After cutting, the files are inspected and assorted as to quality. They are then tempered, any material change in shape due to hardening being rectified at the time of tempering, after which they are ready for final inspection. This consists of trying each file on a piece of hard steel and making sure that it is free from temper cracks. They are next coated with oil and wrapi)e(l in oiled paper, to prevent rusting, after which they are ])acked in boxes, ready for the market. The teeth of a file remove metal by a shearing cut. This is most apparent in the "Single-cut'' files, where the teeth have THE FILE AND FILING. 29 lateral length; but is equally true of the pointed tooth of the "Double-cut" file. A file bites freer on work having a narrow surface than a wide, because fewer teeth come in contact, at any point in the stroke, with the work surface, and consequently less pressure is required to make the file bite. On very thin work the teeth of a "Double- cut" file bite so freely that the danger of breaking them is great. For work of this character the long tooth of the "Single-cut" is best adapted, as its form gives it greater strength, and the shear of the cut is smoother, one tooth coming into cut as another leaves. On the broad surfaces, however, the teeth of the "Double- cut" have the advantage. A file is "tapered" when it is thinner at the point than at the middle, and is "full tapered" when thinner at point and heel than at the middle. The reasons for thus tapering a file are, first to FIG. 22. reduce the number of teeth that come in contact with the work, and, second, to enable the operator to file a straight or plane surface. The first reason is evident ; the second is shown in Fig. 22. If the file is perfectly straight, as shown in i, the motion in order to produce a plane surface on the work must be abso- lutely parallel to this surface. This the most expert mechanic can scarcely be expected to do, and the result will be work rounded at the edges A and B. If the file is tapered, its surface will be slightly convex, as shown in 2, and if moved entirely across the surface, straight work will result. The workman will experience little difficulty in accomplishing this, as he can allow the motion of the file to deviate slightly from a straight line, and stni not cut away the edges A and ?>. If the file is not moved clear across the work, a concave surface will of course result. 30 MODERN MACHINE SHOP TOOLS. The tempering is certain to distort the file somewhat, and it will, as a result, usually be found to have more **belly," as this convex quality is called, on one side than on the other. It is the side having the most **belly," and the highest part of that, that the careful mechanic will always select for use in his most particular work. This high point he readily finds by running his eye along the edge of the file from point to heel. The file does not bite the cast metals as readily as it does the rolled, consequently a sharper file is required for cast iron and brass than for wrought iron and steel. For these reasons tlie new files should be first used on the cast iron and brass, and when they become .too dull to work these metals efficiently, they may be used on the steel and wrought work. A new file will pin and tear the surface of these latter metals much worse than the file that has seen a moderate amount of duty on cast iron and brass. A new file will leave a smoother surface after it has been used for a few strokes, these strokes causing the high teeth to give down a little, which prevents the danger of their scratching the work. The first dozen strokes of a new file on a tough piece of steel frequently lessens its cutting value as much as an hour's steady use on soft cast iron, yet not seriously injuring it for the steel work. Narrow surfaces are exceedingly hard on new files, and especially so on the double cuts, as but few teeth come in contact with the work, and they bite so freely that they are broken off by the excessive strain. Not until the file becomes too dull to be used efficiently on the narrow steel work should it be used on the scale of cast iron or forgings, as this scale is frequently harder than the file. The term "cross-filing*' ai)plies to those filing operations in which the file is pushed endwise across the work. When in cross- filing the character of the work requires a heavy file, it should be held in both hands, as shown in Fig. 23, the end of the handle abutting against the palm of the hand, thus giving a good bear- ing to receive the thrust on the work stroke. When held in this manner an extremely tight grip is not required, which makes it much easier on the fingers and enables the workman to more read- ily control the file. When a very light file is being used on the work it is usually best to hold it with one hand, as shown in Fig. 24. In this case the thumb rests against the side of the file just ahead of the handle. THE FILE AND FILING. 31 and the fore finger extends along the top, considerable downward pressure being exerted by this finger, as near as possible, over the working surface of the tool. When the file is of medium size and thin, if held as shown in Fig. 23, the pressure at the ends will bend it down, making FIG. 23. FIG. 24. FIG. 25. FIG. 26. It concave on its under surface, which will cause it to cut away the metal at the edges, as shown in Fig. 25. If, however, it is hdd a ' '*'"^ in Fig. 26, the downward pressure of the thumb •U 'n the opposite direction, and thus enable the 32 MODERN MACHINE SHOP TOOLS. operator to move it across the work without cutting away the edges. When the thumb becomes tired, the position shown in Fig. 23 can again \)c taken, the ball of the thumb bearing down hard on the file and the fingers lifting at the \K)'\ni accomplish the same object, hither of these methwls of holding is difficult to maintain for more than a few moments at a time, consequently a stitTer file, having considerable belly, is preferable on work of this character. The value of a gcKxl file handle should be appreciated. It should be of gc^od size, well formed, smooth, properly ferruled and, most imiK)rtant of all, so secured to the tang that its cen- ter line is parallel with the length of the file. Handles made of soft, tough wood arc preferable, as they are lighter and less liable to crack when forced on the tang. The soft-wood handle, if pro- vided with a hole for the reception of the tang of a diameter slightly greater than the thickness of the tang, can Ix? driven on without danger of cracking. If of hard wood a good job requires heating the tang red hot and burning the hole in the handle to fit it. Care must be exercised, or the temper of the teeth near the heel will be drawn. A piece of wet waste wrapped around the heel will prevent this. When the work surface is so broad that the file cannot be held, as shown in Fig. 23, on account of the handle striking against the vdfTQ of the work, a surface file holder must l)e used. In I^^ig. 2"^ is shown such a holder. The bottom of the handle is pro- VIG. 27. vided with a tapered, dovc-tail slot to receive the tang, the outer l)oint resting on the top of the file. Before applying the handle file the edges of the tang to api)roximately fit the dove-tail slot, as this may save a jammed set of knuckles. In using a file with this holder, the fingers of the left hand, resting on the top of the file, must give nearly all the pressure necessary to make it cut. The form of surface file holder shown in Fig. 28 possesses the advantage of giving the operator a handle similar in shape and tKJsition to that used rjn onlinarv narrow work. The rod en- THE FILE AND FILING. ^ ables the left hand to so grasp the point of the file that the down- ward pressure may be applied with less fatigue to the hand than in the case shown in Fig. 27. When the handle is screwed tight against the shoulder, the rod draws up on the point, thus tending to give the file more curvature, an advantage of considerable mo- ment in filing accurate plane surfaces. Ordinarily the surface of the work on which' the file is to be used should be held at the height of the workman's elbow, thus allowing the direction of motion of his forearm to be in a line parallel with the plane of the work surface. This position of the work allows the workman's arm to swing freely at the shoulder with the least possible amount of motion at the wrist and elbow. If the work surface is broad it should be held somewhat lower than the elbow, thus enabling the workman to more easily reach over the entire surface. If, on the other hand, the work is of a fine character, depending largely on the eyes and a delicate touch, it should be held much higher. For work of this char- acter the file is usually held in one hand and the high position of FIG. 28. the work prevents the fatigue incident to a bent position over fine work. For heavy cross-filing, which requires a considerable amount of pressure on the file, the workman should stand slightly back from the work with one foot considerably in advance of the other. On the forward, or work stroke, the pressure exerted on the file should relieve the weight on the forward foot, the rear foot bracing against the stroke. On the return stroke the forward foot should again take its portion of the weight, and the file should be relieved from all pressure, but not raised from the surface of the work. Only at such times as it is necessary to examine the condition of the surface being operated upon should the file be taken from the work, its removal for cleaning, however, being excepted. The workman's body should, in heavy cross-filing, move back and forward with the «»*^^^'4^, thus making the back and legs do a part of the T ^ otherwise come entirely on the 34 MODKKN MACHINE SHOP TOOLS. arms. When the work is of a lighter character and the quality of the finished surface rather than the quantity of metal removed must be considered, the workman should stand in an upright position, doing most of the work with his arms. In cross-filing, and more especially where much metal is to be removed, the direction of the strokes ^should be varied fre- quently. This not only enables the production of truer work, but faster reduction of the metal. The file when pushed end- wise produces small grooves or channels in the direction of the stroke, and when the direction of the stroke is changed the file teeth come in contact with the tops of the ridges between the grooves, thus diminishing the area of tooth contact with the work surface, and consequently increasing the bite; that is, for equal pressures. In cross-filing the file should be held at quite an angle with the direction of the stroke, which has the eflPect of giving the file a side motion as it is swept forward. This improves the FIG. 29. condition of the surface filed, prevents to a marked degree deep grooving and brings the file under more perfect control. When the surface is narrow and a large amount of metal is to be removed quickly, the angle at which the file is held may be*' changed, as shown in Fig. 29. As the contact area is small in this case the bite is free. A new file should never be used for this purpose, as the teeth will take hold so freely that they will break off or at least lose their keen cutting edges very quickly. This is much more disastrous on the delicate points of the double cut than the long teeth of the single-cut files. Work of this character should be held close down to the top of the vise jaws, thus preventing chattering. In selecting a file for any piece of work the i of the work surface must determine the shape ai TlllC h'lUi AND FILINC. 35 to use. The hardness of the metal and the amount of stock to be removed, together with the quaHty of the finished surface that is c used Kio. 47. to remove them. These brushes are usually made of fine wire mounted in leather, and tacked to a light wooden back. A stiff bristle brush serves this purpose well, and for very fine-cut files is preferable to the wire. In filing steel and wrought iron, the character oi the ma- THE FILE AND FILING. 45 terial reduces the disposition of the cuttings to pack between the teeth; but, under most conditions, a more serious trouble, that of "pinning" occurs. Cuttings "pin" when they lodge so firmly that they cannot be removed with the brush. Unlike the particles of cast iron, which crowd down below the cutting edges of the teeth, and do not injure the work, but simply re- tard the cutting of the tool, the pin usually stands well above the teeth and scores the work surface at every stroke. The "pin'* can usually be removed by drawing the wire file brush firmly across the surface ; those that resist this treatment being removed by the scorer. The scorer is simply a piece of soft wire flattened thin at the point, and carried broadside, rather than edgewise across the file surface. After a few strokes it becomes serrated and constitutes a short tooth comb, which picks out the pins quite easily. Pinning may be somewhat reduced by chalking the surface of the file, which has also the effect of reducing its bite. A lit- tle oil on the file will frequently reduce the tendency to pin. It should be used, however, only on the fibrous metals, as it glazes the surface of the non-fibrous metals, making them harder to cut. Chalk is usually applied to a file when a smooth, fine work surface is desired. The effect of the chalk is to prevent the teeth from cutting as freely as when it is not used, and thereby pro- duces about the same result as would occur if a finer cut file had been used. It becomes necessary to rechalk the file after each cleaning, an operation requiring some time, and which can, by using the fine file, usually be avoided. When oil has been used on a file it can readily be removed by thoroughly chalking and brushing two or three times, as the chalk soaks up the oil and leaves a dry surface. In fine filing operations, where it is quite important to know the exact spot on the work surface wtiere the file is cutting, the surface can be dimmed after every few strokes by passing the palm of the hand over it. The dry, soiled hand will deaden the surface enough to clearly show where the file cuts on its next few strokes, and will in no way injure the cutting of the tool. Files are frequently injured by improper care while not in use. When boxed at the factory they are brushed over with oil and wrapped in oiled paper, which prevents them from rusting. When this oil has disappeared they will, if exposed to moisture, rust 46 MODKKN MACIIINK SHOP TCX>LS. readily. As there is a large exi)osed tooth surface the deterioration due to rust is rapid. Files should never Ixj thrown together in a drawer, or even allowed to come into contact with each other, or with other tools, as the delicate edges of the teeth are most easily broken down, and the value of the file seriously impaired. They should be kept in a drawer, separated from each other by low partitions, and arranged according to length, section, cut and condition, thus facilitating the selection of any desired file. Any form of file rack, in which the file hangs from its handle, is satisfactory. The tendency is for files to accumulate, a large number that are nearly worn out littering up the file drawer or rack, injuring the good ones and doubling the time required in selecting a file for any piece of work. A number of these partially worn files are quite necessary in the file drawer of the mechanic who is engaged on work of a gen- eral character, as he will very carefully avoid putting the new or better ones on the hard scale of castings or forgings. The machinist should at all times exercise good judgment in the selection of the proper file for any j)iece of work as he cannot otherwise expect to get economical results from the files he uses. Except in cases where his work is all of one character he will ex- perience little difficulty in so selecting that he will always be able to use his partially worn files to good advantage on much of his work, thus saving the new ones for the best work. The broad surfaces of cast metals require the sharpness of the new file to properly cut them, while the narrow surfaces are readily cut by the somewhat dulled teeth of 'the file that has seen a moderate amount of service. Steel and wrought work will reduce the file to a condition where its further use is un- economical except as it may serve to protect the better ones by being used for cutting thin, hard materials and removing fins and scale from castings and forgings. Thin castings, and especially the fins on them, are quite apt to be chilled, making them harder than the file, a condition not conducive to the health of that tool. The sand must be thor- ouf];;hly removed from castings before applying even the {>oorest file, as otherwise, the grindstone action will soon render the file absolutely useless. The sand can be largely removed by brushing, but t only by a chemical treatment which softens rather than THE FILE AND FILING. 47 It. This process, commonly known as pickling, consists in the washing or soaking of the castings in a l)luc vitriol solution, or ed over the face of the" surface plate. The material used for this marking is usually Venetian red tnixeri in oil Reel lead answers fairly well, bl| separates too easily from the oil and does not spread as even^ and tl.in as the former. The markmg can be best applied to tl surface with the fingers or the i>alra of the hand, as the SCRAPERS AND SURFACE PLATES. 51 detects any dust or grit and spreads the marking thinner and more uniformly over the surface than can be done with a piece of rag or a brush. The work surface is now rubbed over the surface plate, the high points on the work being shown by the marking rubbed from the true surface of the plate. These high points, if small and few in number, may be reduced with a fine file until the work, when moved over the plate, will show fairly good contact. The file should be used up to that point in the operation at which more time would be required to make the file cut on the proper spots and sufficiently light to prevent pitting than would be required to remove the metal with a scraper. The workman's judgement must determine this point, and much time and hard work will be saved if his judgment is good. A file hav- ing considerable belly should be used for this purpose. The thickness of the coating of marking will depend upon the condition of the surface, the nearer it approaches a plane the thinner the marking must be. If too thick false bearings will show, which lead to confusion and errors in the scraping. For the finest work it must be rubbed down so thin as to be scarcely visible, and the dark brown spots left on the work will then show true bearing points. The harder the surfaces are pressed together the plainer will the marks appear, the higher ones look- ing the brightest. When the work is heavy and aw^kward to handle the surface plate may be rubbed over it. After each course with the scraper the surface must be remarked. For the first few courses the strokes of the scraper may be moderately long, never exceeding three-fourths of an inch, but as the surface becomes truer and the bearing points close together, the strokes must be made shorter, being careful not to overreach the marked points. Each course must be made at a considerable angle with the preceding one, thus preventing the waved surface that results from numer- ous cuts across the work in one direction. The scraper should be held as shown in Fig. 56, and pressed firmly to the work. The pressure required depends upon the hardness of the metal being scraped and the condition of the cutting edge. This must be carefully considered in accurate fin- ishing, since as the tool dulls the pressure must be increased in order to give cuts of equal depth. The degree of accuracy require^ '*very case determine how far tl tld be c strictly first class 52 MODERN MACHINE SHOP TOOLS. job there should be contact over practically the entire surface, as shown by the extremely thin coat of marking. Such surfaces ^re comparatively expensive to produce. When two plane surfaces are to move over each other, as so frequently occurs with machine parts, both may be trued to the surface plate, but usually the nature of the work will prevent the use of the plate on both, in which case one surface may l)c trued to the plate and the other fitted to this surface. When two plane surfaces that are not intended to move ovtT each other arc to be fitted tojij^ethcr one should, if possible, be trued to the plate and the other fitted to it, but frequently in such cases it is not possible to apply the plate to either surface, and usually motion of the one surface over the other cannot be no. 56. had. In such cases the process known as "bedding" must be used. When possible one surface will be trued to the plate, then covered with marking and placed in position over the surface it is to be fitted to, when a sharp blow with a mallet or soft hammer will cause it to mark the high sjxns on the latter surface. These spots can be scraped away and the process con- tinued until the marks appear uniform over the entire surface. If neither of the parts can be applied to the plate, one must be machined and finished as true as possible and the other fitted to it. This will, of course, not give true plane surfaces, but in nearly all cases where motion between the surfaces is not ex- pected, a imiform bearing is all that is necessary. As before, the coating or marking will depend upon the condition of the surfaoei. If too heavy at any time the force of the blow- will spreai* * SCILVPERS AND SLRl-ACK PLATES. 53 the low spots, thus C2^iving false bearings. Pedestal bearings, con- necting rod brasses and similar parts, must usually be fitted in .this manner. Cylindrical surfaces, as shaft, spindle and pin bearings, also depend largely upon the scraper for bringing them to their true bearing surfaces. In such cases the bearing is usually fitted to its spindle, the latter taking the place of the surface plate. It follows that if the spindle is not round a perfect bearing will not result. Since in machine construction the cylindrical truth of all spindles must be sufficiently exact to satisfactorily perform the operations for which the machine was intended, the bearings may be so fitted. In high grade machine construction the spindles are ground and lapped cylindrically true, thus enabling the skilled workman to scrape the bearings for these spindles as accurately as he could produce a plane surface from a standard surface plate. In the absence of a standard plane a true plane surface may be originated in the following manner: Take three plates, the surfaces of which have been brought to approximate planes. •Determine by means of the straight-edge which of these plates is the nearest true. Call this plate A and the others B and C. Assume A as a temporary standard, and fit P» and C to it. The surface outline of A is shown to an exaggerated scale in Fig. 57. In Fig. 58 are shown B and C placed together after having FIG. 57. FIG. 58. been fitted to A. If now B and C are fitted to each other, being careful to correct equally the error on each, it is evident that cither B or C will be nearer a true plane than A. Now select one of these plates, say B, as a temporary standard and fit A and C to it. Then fit A and C to each other as before. Next select C as the standard and repeat the process. Each repetition of this operation will bring the surfaces nearer to true planes, and when they finally interchange, showing perfect contact between any two, ^ "" ^«is been completed. ^ MODERN MACHINE SHOP TOOLS. Surface plates are designed to resist as much as possible the deflection due to their own weights. In large plates this is an extremely important point in their construction. For the final finishing the plates could be tested while standing on their edges, but if trued in this position they would sag in the center when turned down. It would, therefore, be necessary to apply them to the work in the same position in which they were finished, which would be extremely awkward. A surface plate should always rest upon three points of sup- port and should be kept in a substantial wooden box, from which the cover can be easily removed, exposing the surface when in use and protecting it when not in use from accidents due to articles falling on and marring the face, as well as from the dust. When not in use the surface should be kept oiled to prevent rusting, which would impair its accuracy. The surface plates should be kept in a temperature as uniform as possible and not varying far from that at which the plate was finished, as the expansion due to changes of temperature is very apt not to be uniform and the truth of the plate thereby aflfected. In using the plate, wij^e any dust or grit from the face before applying the work, otherwise there is danger of scratching the surface. A careful workman tests small work on the edges of the plate rather than in the center, and thus prevents dishing the plate through wear. ClBii, ^auif an^) ^x^ Etpprfer, CHAPTER IV. STANDARDS OF MEASURK. Modem methods of manufacturing interchangeable machine parts necessitate the extensive use of standard gauges. A stan- dard gauge is a fixed caliper, the distance between the measuring surfaces representing a certain definite portion of the British Im- perial yard, which is also the standard in the United States. This British yard is the distance between two very fine rulings on polished gold plugs inserted in a certain bronze rod commonly referred to as bronze No. i, and carefully guarded within the walls of the Houses of Parliament. As changes in temperature affect the length of the bar, the dis- tance between the lines is standard at 62 degrees Fahrenheit. The rulings on the gold are so fine that they are hardly visible to the naked eye, necessitating the use of the microscope for making comparisons. A number of copies of the British yard were made for distri- bution among the different governments and to preserve as refer- ence in case of accident to the original standard. Of these only tw^o, bronzes No. 19 and No. 28 were exactly standard, the others varying slightly from the original. Both of these are retained by the British government as exact representations of their stan- dard of measure. By act of the British Parliament, the Imperial yard was legal- ized in 1855, ^^^ ^^^ following year copy No. 1 1 was presented to the United States Government. At 62 degrees Fahrenheit No. II is .000088 of an inch shorter than bronze No. i, and is ex- actly standard at 62.25 degrees. The temperature at which these bronzes are standard is usually referred to rather than the amount of their error at 62 degrees Fahrenheit. The exact subdivision of this standard yard into its thirty-six equal divisions, each of which represents one inch, and the still further divisions to the fraction of an inch was a task of no small proportions. Sir Joseph Whitworth obtained the inch subdivi- sion by making first three end measure test pieces, each equaling as near as possible one foot. Keeping these pieces continually of equ* h they were worked down until the three when =;o MODERN MACllIXK SHOP TOOLS. placed end to end exactly equaled the standard yard. By con- tinued subdividing^ the foot i)ieces were reduced to inches. l''or the fractional division of the inch he depended on the accuracy of a screw. The enormous amount of time and work required to make this subdivision can hardly be appreciated, and when completed the uncertainty of maintaining the test pieces as .uan- dards due to the wear on the measuring faces by the repeated trials necessary in the comparing of working test pieces renders the method unsatisfactory. These uncertainties were eliminated in the method i)ro]X)se(l by F^rof. William A. Rogers and so ably carried out by himself and the Pratt & Whitney Company. This method substituted for the end measure test i)ieces a graduated steel bar, thus making a line measure reference. As workinfj gauges are made of tempered steel, it was important that the ref- erence bar be made of the same material, since the eflfect of changes in the temperature affects to an unequal degree the ex- pansion of different metals. .As repeated comi)arison with the bronze standard would not be practical or even desirable, it was 5r I 4IIIIIIIIIIIIIHIIII iiiiiii|iii|iii iir I iMti iinminmiiiri I I I KIG. 59. decided by the Pratt & Whitney Company to construct a hard- ened steel bar, to be graduated and compared with the official standard, and that this bar, when its precise relation to the stan- dard was established, might thereafter be used as a standard with which to compare steel gauges and t(^ols necessary in the produc- tion of accurate interchangeable work. Of the five bars graduated and compared with bronze No. 1 1 the shortest, a tempered steel bar, 6 inches long and Yz inch square in cross section is the one about which manufacturing in- terests most center. Tlie upper surface of this bar is ground and polished to a perfect plane, and 4 inches of its length grad- uated, as shown in Fig. 59. The subdivisions along one edge are inches, half inches, quarters, eighths and sixteenths, along the opposite edge, tenths and twentieths and through the center a series of lines representing the exact bottom diameter n{ V . S. standard thread gauges from '4 to 4 inches, with a band of rul- ings immediately below of 2,500 per inch. These lines were cut STANDARDS OF MEASURE. 57 with a diamond, and are exceedingly fine, being not greater than 1-25,000 of an inch in width. A complete description of the method employed for ruling and comparing these bars with the standard, bronze Xo. ii, to- gfether with a description of the Rogers-Bond comparator, is given in a book published by the Pratt & Whitney Company, entitled "Standards of Length and Their Practical Application.'* The most careful investigation of this steel line-measure bar shows it to be but five millionths of an inch longer at 62 degrees r^ahr. than 1-9 of the Imperial yard. The greatest error in any of the subdivisions does not exceed 1-50,000 of an inch. By means of microscopes provided with micrometer eye pieces the reading or comparing of lines on these finely ruled bars can be made with the greatest exactness, and at the same time not im- pair in any respect their accuracy by wear, as is the case when using end measure standards. As a measuring machine, the essential features of this remark- able instrument and its working may be briefly stated as fol- lows : Two accurately lapped surfaces corresponding to the anvil and measuring point of the common micrometer serve as caliper points, between which the articles to be measured are placed. The measuring point is secured in the end of a sliding plunger, which carries in a suitable position a small plate, upon which is ruled a very fine reference or setting line. Back of, and capable of motion, parallel with the plunger is a carriage mounted on suitable guides. Secured, adjustably, to this carriage are two powerful microscopes, each provided with micrometer eye pieces, by means of which variations in the setting as small as 1-60,000 of an inch may be read. The standard steel bar is so placed that one of the microscopes passes over its surface when the carriage is moved along its guides. A spiral spring attached to the measuring plunger in a suitable manner provides equal pressure of contact between point and work as between point and anvil. In operating, the surfaces of the measuring point and anvil are brought into contact, the carriage is moved to the point at which one microscope shows exactly over the line on the plate on plunger, and the other microscope is adjusted to read ex- actly on the initial Jine of the standard bar. The plunger is now moved back, and the article to be measured placed between the points. The carriage is now moved along its way until the first MODERN^ MACHINE SHOP TOOLS* microscope again reads on the line on the plunger. The other microscope will liavc moved over the standard bar an amouni equal to the distance between the measuring points, and the reading on the har, with the aid of the micrometer eye piece for the minute suhdivision, will give the exact tneasurement in terins of the standard. Although desirable to maintain the temperature uniformly as near 62 degrees Fahr as possildc. it is not necessary in the meas- uring of hardened steel articles, as the coefficient of expansion, FIO. 60. for these ami the standard bar is the same. It is, however, ver important tliat both the article being measured and the standar bar ]je at exactly the same temperature. In rig, fx) is shown a general view of the Rogrcrs-Bond coin parator, owned liy the Pratt & Whitney Company. With this machine measurements guaranteed correct to tin 1-50,000 of an inch are continually being made in the produ« tion of tlie standard gauges of this company, and differences dimensions as small as 1-100,000 of an inch readily indicated It will lie understood, however, that measuring and indicatir are vast I v different matters, as a difference in dimensions tc STANDARDS OF MEL\SIJRE. $9 small to be read with any degree of accuracy can be readily de- tected* Thus we see that at great expenditure of time and labor a working standard, the rehability of which is beyond question, Vfzs produced. Standard gauges cannot be classed as measuring instruments* as they do not determine the amount of variation when they do nut fit the work. If the work is ver>^ nearly to size, however, the tightness of the fit will give an idea as to how much the work is over or under size; this based on the judgment of the opera- tor, of course. In Fig, 6i is shown a plug and ring gauge. The diameter of bese gauges is, as stamped on them, ij/i inches, as near as hu» man skill can make them. The particular gauges shown are jaranteed correct to the 1-50,000 of an inch. It is perhaps dif* cult to conceive of a dimension so small Take i-ioo of an inch, ^hich is the smallest graduated space commonly put on the ordinary steel scale. Imagine this small distance divided into mG. 61. PIG. 62. equal parts, and then one of these portions into fifty equal irts, and you really have something small in the way of distance, ^though so nearly of the same size, by skillful manipulation, the ^!ug may be made to enter the ring. Both surfaces must be "wiped perfectly clean and coated with fine oil When entered the one vdll move over the other with great smoothness and surpris- ing ease, but if the motion is stopped for only an instant they will set, and so firmly that nothing short of a sharp blow with a mallet will start them. There can certainly be but little room for lubri- cation between these surfaces, and the supposition is that when motion stops the little globules of oil flatten out so thin that the surfaces of the metal coming into contact grip each other. The effects of temperature are clearly shown by first cooling and then warming slightly the plug. In the first case it enters the ring readily and in the latter it cannot be induced to start. These luges are made in any desired sizes, from Vi to 6 inches. Id Fi^. 62 is shown an end measure test piece. This little MOnKRK MACttIXE SH0P TOOtS, [piece of hardened steel measures exactly between faces the ili>- tanct^ stanipeide is to receive a small wooden handle with which to manipulate it, as the heat from the fingers would otherwise affect its length. The accuracy of the method of making and the final m?S3 uring t>f llicse test pieces were shown nit>st conclusively hy tin severe lest of the committee of the American Society of Mechan ical Engineers ap[X)inted to investigate the subject of staudardi atul gauges. The lest consisted of the placing cm\ to eneing i^ one piece, which hatl been previously rejected because of a defc tjve face. Fig. 63 shows a form of caliper gauge, double end patlc for gauging both internal and external dimensions. Forji* larger sizes the forms shown in Fig. 64 are used, as the t STANDARDS OF MEASURE. lighter and more convenient tools. For general shop use» where constant referenct: is lo be made to them, these gauges are pref- craljle to the plug and ring forms, being hghter, cheaper and mere convenient. With the ring gauge it must be applied to the end of the work, while the external caliper gauge can be used at any point in the length of the work. Good judgment must be exercised in the use of all accurate luges. They must never be forced, as in that case excessive rear results, and they soon become unreliable. A standard ring is not intended for measuring anything except work that by care- i! methods has been brought to the gauging diameter. Tt liouid move freely over the work without forcing, and yet close lotigh to show no shake. When it is considered that 1*2000 T»f an incli is the ilifference between a tight and a loose fit, the results possible with gauges of this character become evident. r-^ £0 fk;. 65, In using the external caliper gauge, if forced over the work not only wear to the faces, but springing of the jaws will result* both of which destroy the accuracy of the tool. Never attemin to use this or any other gauge on rotating work, as the faces will catch and draw over work .-several thousandths over gauge size. In die machining of nearly all work, a certain amount of variation from the exact standard size is permissible^ the amotmt 01 this variation depending on the nature of the work. If, for example* the variation allowed in the making of a large number fOi like parts was ,001 of an inch from exact si^te, the econ(»micaI x>iluction of these articles would not permit the loss of time in ^^^ .!..,„ ..„j..T.. riccurate. Tl ' in Figs. 65 and 6fi illustrate external and . nd of the external gauge shown 62 MUUiiLRN M.VCUINJ^ SLiOU TUULS, must pass over work not exceeding .250 of an inch in diameter. The opposite end, which is but .0015 of an inch smaller, mu*t not go over. In this case the limit is all under the exact size. FIG, 66. while in the internal gauge shown in Fig. 66 the limit of .002 is hah' helow and halt' al>ove the standard size. In Fig. 67 are shown United States standard thread gauges, FIG. 67. external and internal By an extremely accurate method, die threads of these gauges are ground after hardening, which leaver them highly finished aticl correct as Ki pitch anrl angle. The statv danl pipe gauge is Illustrated in Fig. 68, The use of standard PIG, FIG* 69. thread gauges enahles the manufacturer of pipe, fitiingii, screws, etc., to maituatn stanilard threads and sizes hy referring alt taps and dies to the standards. The corrective gauge shown in Fig. 69 is use STANDARDS OF MELXSURE. 63 correctness of caliper gauges. To insure against errors aris- ing from the use of gauges which, through wear or accident, have become incorrect, it is important that they frequently be referred to the corrective gauge. Caliper gauges which have worn on the faces until they are oversize, can be brought up to standard by pening lightly the outer edge of the crescent. The use of standard gauges and micrometers has done much to systematize, improve and lessen the cost of many lines of manufacture. With our present excellent systems of gauging it would be quite possible to build the many parts of a steam engine or machine tool in many different shops throughout the country and to assemble these parts into a perfect working machine. In the manufacture of gauges the cost depends very largely on the degree of accuracy obtained. A set of cast iron plugs and rings for common work can be ground correct to one-fourth of a thousandth without much trouble. But when of tempered steel and the error reduced from 1-4,000 to 1-50.000 of an inch, the cost of production due to this great refinement increases many times. Gauges that are to be finished to the highest possible degree of accuracy are, after being hardened, ground to nearly the required dimensions, and then stored away to "season/' Gauges that are finished immediately after hardening will frequently crack open several months later. It has been found, however, that if the gauge is allowed to stand for about a year before the finishing work is done on it, it is not apt to crack thereafter. Gauges are made standard at 62 degrees Fahrenheit. CHAPTER V. CALIPERS. Calipering tools may be classed under two heads — transfer and recording. The transfer class includes all calipers used to trans- fer scale dimensions to the work, work dimensions to the scale, or to receive and transfer from one piece of work to another a dimension without reference to its exact magnitude. The record- ing caliper is provided with a scale which gives the length of the dimension measured as well as forming a transfer instru- ment. This latter class includes the vernier and micrometer calipers. The large and heavy calipers of this class are called **bench micrometers." Recording calipers are usually graduated to read to one-thousandth of an inch, which makes them suffi- ciently accurate for use on all ordinary mechanical operations. When, however, the tool is designed for greater accuracy, it becomes necessarily more delicate and expensive; and is not suitable for general shop work. Such instruments come under the class known as ''measuring machines," which are used as test instruments. The transfer cali])ers are (^f three general forms : firm joint, lock joint and spring, the latter two usually being called adjust- able calipers. Calipers to be first-class should have well proportioned legs made of high grade steel, preferably tempered, with a carefully fitted joint having a uniform amount of friction at all positions of the legs, thus insuring a smooth, steady motion when settlBf. In Fig. 70 are shown at A and R a pair each of outside iliid inside firm joint calipers, and at C a pair of inside lock joint Cri- ijiers. In this tool a tapered socket joint enables the short tfm A to be rigidly locked with the outside leg B by tightening the knurled nut C. The nut D, which is coned on the bottom, movts over a stud, which is secured in the middle leg, and moves through a slot in A. Secured to A is a small conej againit which the cone nut bears, thus forcing the middle leg away A when D is tightened down. A stiflF spring set in the un of A resists the separation and holds the joint steady. may be set to approximately the size desired, the join CALIPERS. 65 and the final adjustment obtained by turning the nut D. By ad- justing C to give the correct friction this tool may be used as a firm joint caliper. At D, Fig. 70, is shown a good example of the numerous forms of spring calipers in use. Its construction is clearly shown in the figure. They may be had with solid or slip nut on the screw, a slip nut being shown at E, Fig. 70. It is a split nut pivoted at A with a light spring in a recess inside the knurled head, which holds the halves together at the threaded end, the outside of which is coned to fit a recess in the post or caliper leg, which prevents the nut from opening when the tension of the joint spring is upon it. The slip nut saves time in setting the caHpers, FIG. 70. which is of material importance where numerous settings are to be made. The skillful use of transfer calipers depends entirely on the good judgment and delicate touch of the operator. He must recognize contact, between the points of the caliper and the work, without pressure. The ability to make a sure calipered fit is an accomplishment that comes only with practice. In set- ting calipers to a scale care must be exercised, the chance for personal error being great. In setting the outside calipers the scale should be held vertically in the left hand, with the end of the little finger resting against the side at the bottom end to sEt.'.tdv the iinvcr pnuu ut llic caliper^ <>v'er ihc end of the scale, the caliper being lield in the right hand» as shown in Fig. 71. If the caliper is a "firm joint'' it most bt* adjusted to the re- quiri'd w dimiuii^hing A^ i^IkF ^^U^^^^"^^"^ is obtaic^V 9tK the adin^t^ift-H ^^^^M^ should b«' 1^ 66 MODERN MACHINE SHOP TOOLS. held in the right hand, as shown in Fig. y2, the thumb and fore- finger operating the adjusting nut. The upper caliper point rests against the side of the scale and over the graduations. The lower point rests against the end of the scale, hut the eye must determine when the u])per point coincides exactly with the re- quired reading. The end of the scale should be square, only a no. 71. comparatively new steel scale being suitable, as an old one is fre(|uently worn enough to make it a])preciably short. When the caliper is heavy the little finger of the right hand should be pressed against the lower leg to steady and sup])ort it. The slight angularity of the points with tin' j)lane of the scale, due to dropping the lower point below the graduated surface, has pk;. 72. an a])precial)le effect on the accuracy of the setting only when adjusting for the smaller dimensions. This error may be avoided by slightly twisting the caliper so as to sj)ring the legs sidewise enough to bring the points in planes parallel to the surface of the scale. CALIPKKS. 67 In setting the inside calipers to the scale the end of the scale should be placed against and held at right angles to a plane sur- face ; one point of the caliper placed against this surface and the other adjusted to the required reading on the scale. It is very important that the scale be held perfectly at right angles, as a slight variation makes considerable error in the reading. It is not good practice to set both points to lines on the scale, as the chance for error is much greater than when the measurement is referred to one end of the scale. In transferring a setting from one pair of calipers to another, the reference pair should be held in the left hand, with the lower point resting against the end of the little finger. The lower point of the pair being set should be brought in contact with this point, the end of the finger serving to steady the points. The upper point should then be so adjusted that it just makes contact with the upper point of the reference pair. The accuracy attained depends entirely upon the skill with which this adjustment is made, other than the slightest pressure between the points serving to distort the measurement. Assume that a shaft is to be turned to 4}^ inches in diameter and a hub bored to fit this shaft. The outside caliper will be set to size, as shown in Fig. 71, involving the first chance for error. The bar will now be turned and finished to the caliper size, allow- ing a second chance for error. The third opportunity for error arises in the setting of the inside to the outside calipers, and finally the fourth in jDoring the hub to the dimension of the in- side caliper. Of these the first two aflfect the diameter of the work and the last two the fit. In using the outside calipers they must pass squarely over the work, just touching it. The lighter the touch the greater the accuracy attainable. For final calipering the work must be sta- tionary, as a rotating piece will draw the calipers over long be- fore they are down to size. When a number of pieces are to be turned to sample, it is permissible to set the calipers so that the contact will just sustain their weight, turning all of the pieces so the contact will be the same. This, however, can hardly be called calipering. In setting the inside calipers to the outside, the contact be- tween points should be, as near as a delicate touch can deter- mine, the sam^ « contact between outside caliper points and the wo*' t^ld then be bored to that diameter 68 MODERN MACHINK SIIOI» TOOLS. which gives the same contact between the inside calipers and the walls of the hole as between the inside and outside calipers. The caliper shown at A in h^ig. 73 is technically known as a ''transfer" caliper. Frequently it is necessary to caliper a piece of work the shape of which makes it impossible to remove the calipers without loosing the setting. In this tool the leg .\ is secured to the blade I» by the stud and nut C, the stud striking against the end of the small slot. The caliper is then set, for example, to the larger diameter of a chamlxrred cylinder, and the joint nut tightened, securing D and B to each other. C can now be loosened and the leg A moved to allow the tool to be removed from the work. When moved back against its stop it will show the original setting. Only cali|XTs of the very l)est construction should be depended upon for this kind of work. i-io. 73. The thread caliper is shown at i> in Fig. 73. It has wide, thin I)oints for calipcring both the top and bottom of screw threads. M L\ Fig. 7^. is shown a hermaphrodite caliper, a tool having one calii)er and one divider leg. The divider leg is preferably adjustable, and when caliper is of the spring pattern the caliper leL*^ must have right and left feet, as the legs cannot pass by each other as with the firm or lock joint patterns. This caliper is a valuable tool for centering, and .scribing purposes. The key hole caliper, shown at 1) in Fig. 73, is a valuable tool on work the shape or position (tf which will not allow the usi of two curved legs. The vernier caliper, an examj)le of which is shown in Fig, 74, is a form of beam cali])er which depends for its setting on a graduated scale on the side of the 1:>eam, the subdivisioo of the CU-rPERS. 69 aduation on die beam being obtained by means of tlic ver- nier on the sliding jaw, Thh tool possesses the advantage oi ^>% ide range and comparatively light weiglit. Its value as a nieasur- ig^ instrument depends on its accuracy of consirtiction, cheap ilipers of this class being of little value. The jaws should be of )ol steel, carefully tempered, and the faces ground exactly parallel with each other* The sliding jaw is given its final adjustment by means of the small knurled nut and screw in the auxiliary .;lide. J The graduations usually read to thousandths on the front side of le l)eam, and to sixty- fourths on the back. They may be used tCIS-either inside or outside measurements, but for inside readings "the vernier side a constant equal to the space occupied by the oinis must be added. On the hack side of the instrument two ero h'nes are used, one for inside and one for outside measure- lents. thus avoiding the necessity of the addition for the inside ladings. In explanation of the use of the vernier: Referring to Fig. 74, FTG. 74. will be noted that the scale on the beam is divided into inches. tenths ami fiftieths, and that twenty tlivisions on the vernier pver exactly nineteen divisions on the scale. This makes each pvi&ioti on the vernier 1-20 of 1-50 less than a division on the ale, or t-iooo of an inch. In the figure the zero on the vernier ids at ,2 inch ; if, now* the sliding jaw was moved out imtil |e 10 on the vernier coincided with the next line on the scale inch) it would have moved through 10-20 of r-50 = tlQO or .21 inch from zero: and in like manner if the fourteenth rion cm the vernier bad moved to coincide with the third line 70 MODERN MACHTXR SHIOP tOCHJi. beyond ifi itichcs, as shown in I*'ig. 75^ the reading w^iMild k^ I inch -f ,3 inch -f 4-50 (,o8> + .014 = 1*394 mdics. * Hhcr grailuaiifm* than the one shown may be UM-d ; f«j example, if ihe beam is graduated into forty lines per indi and ih vernier hiis twenly-fivc divisions covering iwenty-four on tin ^cale, then each division will be 1-25 shorter than one en tlic s^:al( and 1*25 of 1-40 ^= 1-1000 of an inch, A magnifying glass is of great value in reading these instr J u.. 75, Its, especially so when main rca are to be made in a 1 space of liiiHN ii being very Irving on the eyes. ^^ The micrometer caliper , a skeleton view of which is shovrn Fig* jfi, is a liKil that has conn- into very general use amon mechanics employed on work requiring uniformity and accurac Its simplicity and relatively low cost make it an instrument F v^^ even the mechanic on comparatively coarse work can alTord not to have in the caliper drawer uf his tool chest* I Ir'sc calipers may be divided into two classes, the yoW the Ijeani fialtvrns, Fit^. 76 illustrating the former. In tl the construction i^ (|uile clearly shown. The shank ♦ contains at its outer end a split nut, which for aes will coincianie plane in the anvil As a shar^i \' thread is in section an equilateral triangle, th side* of the threads are equal to the jnich of the thread and th depth of the tliread is equal to the side multiplied by •8f3(i — th pitch X -9*y^ = WiTi X \vherc X equals thr nfimfirr nf tlire per inch* ,Vs the pitch mw \> i^nc-halt the ricpth • i liic mr'-'ati i>n side, the pitch diameter i§ the whole fh'ameter less the depth one threads The cali}irr reading^ ^ therefore in any case the fu cHameter less the depth of one thread, which is determined abore. For the Unite*! States Standard threads the iiitch diameter i ^eaier tlian for the V thread, inasmudi as tt i§ flattened at top x r'^ vm. 81. ViL root an amount equal to one-eighth of the pitch, thus making it« depth one-fourth le^s than with the \ threads. In delermmtng the caliper rcaiJing for the L'niteci States S thread the constant is three-founhs of ,80fi. or .64U5- which dividcil hy the number of threads and subtracted from the normal diameter gives the caliper reading as before. Micnimeter calipers of greater capacity than 2 indies Have tmtU recently* been Utile used. The introduction of the reliable, iBoderate-priced caliper, shown in Fig. 82. has met a popular dnnand for a yoke caliper of large size. It is a mtich more con- venient tcKiI for the work-man than fixed caliper gauges* TIkt tion is a bulbed I. which gtl^riWM^AMHHBsiHi] and CALIPKRS, 75 an excellent grip for the fingers. All adjustments for wear are m the head. Fur the table ol decimal equivalents usually stamped the yoke the following is substituted : Every fifth graduation the barrel (*I25 inch) is extended, and beginning at the zero "marked i to 8, inclusive, tbus giving an inch graduation by jhihs. On the thimble are stamped the tlecimal equivalents for |6 inch, 1-32 inch and 1-64 inch, thus giving a contracted 1 vers ion table, the application of which requires at most only a iple calculation, thus. 2^-^2 inch ^= ^i inch -j- 1-16 inch -J- J2 inch. Set to the 5 and add the sum of the decimal equivalents lor 1-16 inch (.0625 inch) anrl 1-32 inch (.0312 inch ) =^ -0937 inch, which should be set back from the >^ in the ordinary manner. Tills does not interfere with reading the caliper decimally in the onlinary wav. This caliper is made in twelve sizes, from 1 to 12 inches. The I'inch to 6-inch sizes have yokes made from drop forgings of bar steel, and the larger sizes have yokes made of stee! castings, all neat I \ finished and japanned. The face of the anvil is formed by a hartlened steel plug of same dian^tcr as the end of the measuring point. The measuring range of each size is i inch, and for adjustment all sizes other ihtn the i-bich caliper, standard end measure lest pieces are required. Tn cah'pers of this class the yoke is frequently lagged with wj or ban I rubber to prevent the expansion and consequent ccuracies thai arise from handling with the wartn hand. I A form of yoke micrometer in which provisions are made for tdcr range of measurements is shown in Fig. 83. It is made four sires having a range of from o to 12 inches. The anvil mtcd in the end of a spindle, which is provided with stops MODEKN M ACIJINE SHOP TOOLS. acily I inch apart, A slight tum of the anvil spindle wh either stop is tiJ be used brings it firmly against its scat, in whic position il is securely clamped. Beam micrometer calipers are illustrated in Figs. 84, and c%. In each ease the regular micrometer head of one inch capacttyl FtG. 84, mo. 85. FIG. 86. Js mounted upon a suitable slide which moves over the t>cain_ the instruna^nt. Three distinct methods, however, of nmkifl several inch settings are employed. CALIPERS. // In Fig. 84 the inch settings are made to accurately gradiiuted Uings on the beam. In Fig. 85 these settings are made by inserting the tapered steel pin in the holes in the sliding jaw and their corresponding holes in the beam. A separate set ^ji holes is used for eacli set- ting. The holes are bushed witli hardened steel bushings ground and lapped to fit the tapering plug. In Fig. 86 is shown a beam micrometer of six inches capacity. The sliding jaw carries a regular micrometer screw head of one inch range and moves over a cylindrical barrel in which h an accurately lx>red hole to receive three end measure test pieces, fine, tw^o and three inches long. An arm on the head extends into the bore through a radial slot in the cylinder, and by means of the test pieces enables the setting of the head at fixed distances FIG- 87. pe inch apart. A zero mark on the cap and barrel determines proper pressure on the test pieces for each setting. The capacity of the beam micrometer for measuring flat work is limited only by the length of the beam. l'*or round work the height of the jaws limits the diameter, usually to about 4 inches^ [ice in order to keep the weight of the instrument wnthin rea- dable limits it is not advisalile to make the jaws much greater rin 2 inches high. In Fig, 87 is shown a bench micrometer for measuring all size.^. from zero to 2 inches. It has a twenty-thread screw with fifty divisions on the dividing head, thus giving direct readings to f-iooo of an inch. The zero adjustment is obtaine;in on the side of the bed is a standard measurement bar in i% surface of which are inserted hardened steel phigs at intervals one inch. ( )n the (lolished surface of eacfi plug is a wry tii| ruling, the distance from ruling to ruHng Ixing one inch af degrees FahrenhLil within a limit nf rrrnr of 1-50,000 of an ?ncl To one end of the bed is secured a headsiock which carries FIG. 88* fixed measuring point. This |Kiint is secured in a plunger bacM up Ijv a light helical spring. Secured to the plunger s$ auxiliar\ jaw which holds between its face and the face of anotF jaw secured in the head a small cylinclrical ping gauge by fricic alone. Tlie tension of the spring is sufficient to hold the SE gauge at an angle from ttie vertical. The ni(»vahle heacl carries the micrometer which consists of] So-thread screw aiifi a dial having 4ixit of con- tact giving the gauge <»f the matt-rial. When used for gauging plates, this gauge should be made with open end, as shown at C. On the one side is graduated the ICnglish anon the market at a reasonably low price, high accuracy requirements in their maiuifacture oantiot be attempted, l-'or all orditiary gaugfing ihey GAUGES AND INl»U ATOKS. «5 will tic found sufficiently accurate, and vvlun greater exactness is demanded llic niicnjinctcr caliiier shnuld lio nscd, tin; decimal eifiiivalent of the Rau^e rot|uiretl btinj^ taken fnnii a talile on tlie liack of the j^^au^c. In Fig. gs is shown a drill g"aiigc. Stubs* drill sizes, froni Xo. I to No. 60. .\ smaller size with lu>les from Xo. 6f to 80. is made. It may also he bad v\ iih holes from 1-16 to '/■ inch, vary- ing by 64ths, the latter being known as the "'jobbers' '* C ^ /■ ^. these gauges are quite necessary. The iiitl and washer K^aug;e shown in Fig. 96 is so graduated 10 show readily the diameter of holes within its capacity* A m" convenient feature in this gauge is the climensions giving cif boksi lo lap United States standarti threads, .\ gauge this kind wilt be found excellent for nieasuring small holes narrow slot^, whi«'b rar^ o.r, imall to !>e calipered, and fre- oeiitly in inaccc<^«iihl* e thev cannot be scaled. 86 MODICHN MAlHINi: SllnJ* TCKJUS. In Fig. t;7 is shown a center gfauge, which» as its name tnd cales, is used fcjr ^aujE^in^*; latlie :incl nthir machine centers, i turning or grinding them. It may also he used as a gauge fo ? ] -> CENTRE GAITQE, ■ AND 1 GAUGE FOR GRINOrNG AND SETTING SCREW TOOLS. Fir.. 97, grinding and setting threading tools, a nunilxr ui 11 s uses in thi connection being clearly shtnvn in this figure. The angles arc degrees, and the lahle of erjiiivaknts shown is to determine tJ GAUGES AND INDICATORS. 87 proper diameter of hole for tapping full V threads. In this t^iblc the numbers in the first and third cohuiius are threads per inch, jnd those in the second and fourth cohmins the double depth of threads of the corresponding pitches. Thus the tap drill for FIG. 98* l^ tap. 10 threads per inch, \vnulc 7s — '^73^= *577 = 37"^4 kh. The screw thread gauge is shown in Fig. 98. The one 60 FIG. 99, notch will gauge all \' threads ; the others, however, re Rattenerl al the root by the amount the top of the thread is It off in the various pitches of tlie L'nitcd States standard 88 JMOnCRIif MACnilCK SHOP TOOlS threacL These gauges are for use in grinding threading ic and may be had for worm, Whicwcmh and **Aaiic j^tandard threafU. The Acrew pitch gauge. Fig. 99* has a large numljer of ill blades which i*M up into a !»uitab1e handle. Each blade k two ur mure teeth, of the pitch corresponding to that stamp oil the blade* Uy direct conifiarison w*ith a screw threat! ti exact pitch may be determined without the danger of crro lliai arisen when the threads are counted over the edge of a niJ The decimal following the pitch numlicr on t-ach blade is tl double depth of the thread. The thickness gauge, shown in Fig lOO^ consists of a rmml>cr of thin steel leaves, varying by the FIG. 102, Pin. 101, sandtlis in thickness. The leaves may be used singly ur togethei! thus making any thickness ilesiretl within iht^ limits of the tuolj The value of a tr'ol uf thib kind can only be learned by having oiv in iht vest pocket, where its convenience to hand will find manj chances for its use. GAUGES AM* IMrU AJDKS. 89 The depth gaugfe, an example of which is shown in Fig. lOT, is used for measuring thf rtani, as machinist undoubtedly uses it more in general niachinc shq operations than all the others combined. The principal use this tool is in determining the parallelism of one plane with an other, usually the surface of the work with the machine tabh housing, cross-rail or other reference planes. In lesting^, crec ing and setting up work on machine tools the surface gauge indispensable. The simpler the gauge is made the better it is, as numerou FIG. 104, tricks and devices on a tool of this kind usually complicate an decrease rather than increase its value. In selling the point of tM needle to a line or point the clamping screw^ should be so adjust^ that the needle moves smoothly yet with considerable frieiic The powxT applied to the needle to turn it should be on opposite side of the fulcrum from the work, as in that case sprhig of the needle is outside of the fulcrum and the point nial where placed. If the force is applied inside the fulcrum tf spring will make it difficult to set the point as desired. Wticn^ | with the gauge shown, a screw adjustment is provided, the setting is made witli this adjustment. GATGES AND INDICATORS. 91 In Fig. 104 is shown a form of adjustable limit gauge. When used as a limit gauge the uuter screw is adjusted to the maximum allowable dimension and the inner screw to the smallest allowable dimension. The w^xk to i^ass inspection must pass through the outer gauge and not through the inner. This tool when used as a snap gauge is provided with but one screw. It is customary to set the gauge on a plug or other standard and by means of the jamb nut lock the screw in posi* tion. The screws and anvils are hardened and ground. A test indicator is a tool used in determining small variations from the true rotation of a cylindrical surface and irregularities or inaccuracies in its cylindrical truth. It can also be used in determining the inaccuracies of a plane surface, and small PIG, 105. amounts of tm] or lateral motion, as for example, the end motion of a spindle or the dedection, give or wink between gibheetween adjusting screws near the pivot, provides for the con- venient adjustment of the pointer to the zero reading, no matter what the position of the arm. Instruments of this character must be carefully made, and are of great value in the erection and testing of accurate machiner}-. When, however, only an indication of untruth is required, as in the chucking, centering or setting up of work, a much cheaper tool serves the purpose, as for example, the one shown in Fig. io6. In this tool the pointer is held in a universal socket, which is carried on the end of a bar of suitable form to clamp in the tool post of the lathe. If the point is brought against the rotating work, the amount of motion at the outer end of the ix)inter indicates FIG. 1 06. the extent to which the work is out and the way in which to move it in truing. It is a superior method of truing nice work, which will not injure its surface, as is so apt to be the case when trued to the point of a lathe tool. ( )ne of the neat applications of this tool is in the centering of a piece of work, in the chuck or against the face plate, to a point. The sharp end of the indicator pointer is set in the point to be centered, and the work revolved. This causes the outer end of the pointer to describe a circle, the diameter of. which deter- mines how much the jjoint is out of center. By properly set- ting the instrument this circle will be described around the tail center, and when the work is exactly centered the pointer re- mains stationary in front of the tail center. The above serve to illustrate a few of the many applications of an exceedingly satisfactory, yet not extensively used, class of test tools. CHAPTER VII. RULES, SQUARES AND OTHER SMALL TOOLS * No tool in the machinist's kit is more often referred to than the steel rule. Upon it he depends in making all ordinary meas- urements and for the setting of his calipers and dividers. In Fig. 107 is shown a standard steel rule or scale. They are made in various lengths, from one to forty-eight inches, with any de- sired gradation, not exceeding i-ioo of an inch in fineness. For shop work the graduation most used is eighths, sixteenths, thirty- seconds and sixty-fourths, on the four comers of the scale. A scale graduated sixteenths, thirty-seconds, sixty-fourths and one- hundredths is convenient, as the looth graduations will serve for measurements when required in decimals. U Where all the work is measured by fractions, however, the former is the safest \ H ^ nliinfiMiiiulMiM,iiiniflMM[i FIG. 107. ruling to use, as there is then no danger of inadvertently mis- taking a tenth for an eighth division, etc. For this reason, rules graduated in twelfths and fourteenths should not find their way into the machinist's tool box, as he will not have occasion to use these divisions, and their presence will call for greater care in selecting the proper division, with the loss of time incident to changing ends with and turning over the rule in order to get at the division required. The end graduation, as shown in Fig. 108, is frequently very convenient in taking measurements in re- cesses where the length of the scale would prevent the use of the regular gp-aduation. \ Standard steel rules, as made by our leading makers, are re- markably accurate. To be sure, the length varies slightly with the changes in temperature, but thesexhanges are not ordinarily great, and the material measured ^ * affected about the 94 MODERN MACHINE SHOP TOOLS. same amount in the same direction ; so we may feel assured that any errors arising frorn this source are well within the limit of the personal error of the operator in making a measurement. The late refinements in the manufacture of steel rules have enabled the production of very accurate tenlpered ones on com- paratively thin steel. What we usually know as the standard rule, however, is graduated on thick steel, and is not tempered. The tempered rules possess the decided advantage of resistance to wear. An untcmpered rule is easily mutilated, and soon rounds its corners through wear, making its ends unfit for ref- erence. The tempered rules may be classed as heavy, tempered, semi-flexible and flexible. The heavy are about one-tenth: the tempered, one-twentieth : the semi-flexible, one-fortieth, and the flexible one-eightieth of an inch thick. For general work the heavy or tempered will be found best suited. The flexible are PIG. io8. IIIIIIIMIIlillll-ll |lt|lllllllllllllll « \ 10 u lU u Mill llllllillilll 10 " 1 II MMlffJ Iftll llllllll till Id n 1 1 1 IIHill imiiiimmii lllilllUUllli K 10 10 •) 1 1 1 i ! 1 l| li L ff X FIG. 109. graduated on one side only, and are of value in measuring curved or irregular outlines, j In this connection it will be well to call attention to the gear rule shown in Fig. 109. Its application is in the sizing of gear blanks and where, by rule of thumb, two diametrical pitches are added to the pitch diameter of the gear in obtaining the whole diameter. Thus, if the pitch is No. 7 diametrical and the num- ber of teeth 34, then the pitch diameter =^ 34-7 = 4 6-7 inches, and the blank or whole diameter = 4 6-7 -|- 2-^ = 51-7 inches, which can be taken directly from the scale. This rule is of g^eat convenience where many blanks ior varying pitches and num- bers of teeth are to be sized. In Fig. no is shown a neat kink which will be found of value in taking measurements similar to the ones shown in the figure, as well as for setting inside calipers. The hook may be quickly removed. It is hardened, and in connection with a tempered rule forms a reliable tool. In Fig. Ill is shown a' standard steel square. This tool is RULES. SQL' ARKS AND OTflER SMALL TOOLS- 95 nade of cast steel, tempered and accurately finished. The two sulcs of the angle are called the blade and the beam, the length of the blade being measured from the inside of the beam. The form shown in Fig. 112 is preferable when the length of the blade exceeds eighteen inches, as it can be more readily repaired in case of accident./ Either of the methods shown in Figs. 113 and 1 14 may be used h\ the machinist in testing the accuracy of a square, the latter being the more exact of the two. In Fig. 113 A is a plane plate - "71 X .... r 1 J Li,i'[infpi'jiLL'i"l FIG. III. FIG, iro. E — r^ A I \ B Id! c i ** ill G J FIG. Tia. FIG. 113. PIG. 114. of iron with one edge, B C* perfectly straight. The surface A should be smooth and true. The square is first applied as shown at F and a fine line D E scribed along its ^dg^. It is then re- versed to position G, when, if the edge exactly lines with the ruling D E, the square is correct, If» however, the edge and line do not coincide, the square is inaccurate by one-half the varia- tion as shown. Since this metliod depentls for its accuracy on fhe eye of the operator it cannot be called an exact one. The method shown in Fig, 114 reduces the amount of the personal error* since the eye detects readily the ray of light that passes through an exceedingly small opening. In the figure the cvlin- 96 MODERN MACHINE SHOP TOOLS, n a cylindrical surface parallel with the axis may be drawn. While it is in- tended for use on external surfaces, as shown at A, Fig. ii8» il will at times serve a good purpose on internal, as sho\%*n at U, FIG. 117. PIGS. 1X8 AND 119. same figure. A form of box square, shown in section in Fig. 1 19. iK)ssesses the advantage of wider range than that of Fig. 1 17. In Fig. 120 is shown a pair of key rule blocks attached to a common steel rule thus making a very simple and efficient key seat rule. For a great deal of his work the machinist is satisfied with using the edge of a good steel rule to determine its straightness ; hut when he wants to know to a certainty that the work is straight it is a source of great satisfaction to l)e able to refer to a standard straight edge Such a-straight edge is shown in V'\^, 121. It is a piece of steel of thick-ness depending on its lenj^^th, nicely finished, with its two edges parallel with each other anrl 98 MODERN MACHINE SHOP TOOt^. straight. They are rej^ularly made up to six feci in length. Miq a tool being about three inches wide by three-eighths of an in FIG. 1 20. thick. Up to four feet in length they are frequently tempered i the edges. A cast iron or surface straight edge is shown in Fig, 1 22. a FIG. J 21. Tliese tools are designed for an entirely different class of than the one shown in Fig. 12 i. The edge is wide and scrap to a true plane, with the hndv sd formed as to best resist defll FIG. 122^ ^jion from its owti weight and distortion due to dianges iit prature. These straight edges are used in the production long plane surfaces like planer bed \**s and lathe shears, RULES, SQUARES AND OTHER SMALL TOOLS. 99 a view showing how it should be ground. When the screw driver. A, is applied to the slot of the screw head it bears onlv • — DC at the center of the upper edges. rp^ r""^^ C and I), of the slot, and the force I I I J ro(|uircd to turn the screw forces the driver out of the slot, which ^^^' ^^^' injures, if not completely ruins, the head of the screw. With B the case is different. The j)arallel sides of the bit take squarely a bold of the sides of the slot and the screw is driven without in- jury, and with much less exertion than in the former case. The screw driver should be made of good tool steel and given a tougli temper. In Fig. 126 is shown that much used tool, the monkey wrench. This is a genuine wrench, and should only be used as such. It should never be used as a hammer ; neither should it be expected to stand all the force a thoughtless workman can apply at the end of four feet of gas pipe slipped over the handle as an extension. It should, however, when properly closed on the flats of a nut. RULES, SQUARES AND OTHER SMALL TOOLS. lOI Stand safely all the average man would care to exert with both hands on the handle. As the nut often starts more easily with a quick jar or shock than by the application of a steady force, it is permissible to strike the end of the handle in the direction shown by the arrow with a rawhide or wooden mallet, or the end of a soft block of wood. The operator's judgment must determine how heavy a blow he can safely use. The surfaces A B should be smooth, plane, and parallel with each other. These wrenches usually fail by bending at C. If the bend is slight, A can be most easily made parallel to B by filing, but when badly bent it should be carefully straightened. The jaws of the wrench and the nut or square upon which it ^ c \\ 'J FIGS. 126 AND 127. is being used will be least injured when the jaws are closed firmly on the work. This necessitates slackening them slightly and closing again every time the wrench is changed. By giving the hand a slight rolling motion around the handle, with the fore- finger against the knurled head of the wrench screw, a sufficient amount of motion can be given to the sliding jaw to close on and release from the work without loss of time. The sliding jaw, due to its long bearing on the shank, is m.uch stronger than the fixed jaw7 consequently the wrench should be operated in the direction of the arrow. Fig. 126. An examina- tion of Fig. 127 shows that when turned as above indicated the maximum pressure comes at B and C, which places the shorter I02 MODERN MACHINE SHOP TOOLS. leverage on the weaker jaw. If turned in the opposite direc« tion the pressure comes at D and E, which increases the bending tendency at F, and also the pressure on the screw. The great variety of combination wrenches on the market pos- sess little merit. When we use a wrench we do not want to have a hammer, a screw driver, a nail puller, and a dozen other **uscful tools" in our way at one time. When finished standard nuts are to be turned the solid wrench is preferable to the adjustable, as it can be made to fit closely to the nut with less danger of injuring it. In Fig. 128 is shown a finished case-hardened, solid wrench. The angle of the open end is fifteen degrees with the length of the handle, which enables a hexagon nut to be turned when the wrench can \ye carried Kic.s. 128 TO 132. through thirty degrees only. Hicse wrenches may be had double ended. The box wrench has a closed opening, as shown in Fig. 129. This particular form is commonly called a tool post wrench. The socket wrench, shown in I^'ig. 1 30, is made for square and hexagon nuts and cap screws, which are to be oj^erated upon in deep or inaccessible places. When a great many small nuts are to be quickly set, the socket wrench, in Fig. 131, operated in a bit bracCj does the work rapidly. It frequently happens that a nut must be turned which is in so inaccessible a place that the handle of the wrench can be car- ried through only a few degrees. In such cases, the ratchet wrench, shown in Fig. 132, serves its puri)ose well, the effect on the nut being much more satisfactory than when the set chisel and hammer are used. In the use of all solid wrenches they must fit the nut closely, as otherwise both nut and wrench will be injured, the nut rounding and the wrench spreading. CHAPTER VIII. DRILLS The twist drill which has come into such universal use, has superseded the old, flat, forged drill which, for so many years, held without rival the first position as a tool for producing cir- cular holes in metal. For the needs of its day, it served its purpose well. The advancements along mechanical lines demanded a better tool for this work, however, and the twist drill resulted, brought out in practically the same form as now used, the prin- cipal recent improvements being mostly in slight changes in form, and its more accurate production due to improved methods of manufacture. The flat drill, as used for metal work, is generally of the form shown in Fig. 133. It is made from round stock, is forged thin at FIG. 133. the lips, and ground as shown in the figure, with three cutting edges — A, B and C. This is a very accommodating sort of a tool, being capable of producing a number of holes of different diam- eters, yet, approximately equal to the width of the drill. The dis- advantage of this adjustability, however, lies in the fact that the size of hole wanted cannot ordinarily be produced. The flat drill has no lands, as that part of the twist drill be- tween flutes is called, to steady and guide it in the work. Conse- quently, the hole drilled will usually not be round, and should the point of the drill strike the side of a small blow hole or soft spot in the metal being drilled, as frequently happens in working cast 104 MODKRN MACHINE SHOP TOOLS. metal, the point will drift toward this spot, thus making a hole that is neither round nor straight. This is shown at A in Fig. 134. In order to drill holes approximately to size with the flat drill, it is necessary that the cutting lips be most carefully ground. The angle of the lips with the axis of the drill must be equal, other- wise one cutting edge will perform all the work, and will dull quickly, due to this double duty. The pressure on the cutting lip will crowd the point, causing it to revolve in a small circle about the center of revolution. This will cause the other flute to cut slightly at its outer end, thus producing a hole of larger diameter than the width of flat. This is shown at B, in Fig. 134. The cutting lips should be of equal length, with their intersec- tion in the axis of rotation of the drill. If one lip is longer tlian the other, the diameter of the hole drilled will depend on the fk;. 134. length of this long lip, as it will rotate about C, its central axis. as shown at A, in iMg. 135. In case the intersection of the lii)s does not fall on the axis of the drill, the one lip is thereby made longer than the other, and the hole drilled will again be large, as the tool will spring an amount sufficient to allow it to revolve about C instead of its true axis, and the length of the long flute again determines the diam- eter of the hole drilled, as shown at H, in Fig. 135. The first cost of the flat drill is small, and the results obtained by its use usually poor. Its only advantage lies in the fact that It can readily be forged and tempered to do work on extremely hard metals. The flat drill, ground thin and tempered hard, is a valuable tool for drilling hard steel or chilled iron, as it will in that form take hold of metal that the twist drill will not touch. It also makes a convenient extension drill, as it can be readily *onne(l on the end of a long bar c^f steel. DRILLS. 105 The flat drill is not adapted to the drilling of deep holes, as it does not free itself of chips. It is largely used for roughing out cored holes, pi:eparatpry to boring, which work is yct\ destnic- tive, due to scale and sand, to the land clearances of twist drills, \\'hen so used in a lathe, the drill is held against the dead center and fed forward by the tail screw, the work revolving. About i860, twist drills, having milled flutes, were first placed on the market. Previous to this date, however, drills with flutes produced by filing and the twisting of the flat stock had been used to a limited extent. In Fig. 136 is shown a taper shank twist drill. A A are the flutes, B B the lands, C — ^the metal between the flutes — the web, D D the lips, E the shank and F the tang. The center or grinding line is the fine line rimning along the bottom of each flute, and fk;. 136. serves as a guide to tht lips in grinding so their intersection will fall in the center of the drill. The three clearances in the twist drill arc : first, the "body clearance" of one-half to one-thousandth of an inch per inch of length of the fluted portion ; second, the "land clearance" of about one-half of one circular degree as shown at A A in the end view, 1' JR- ^37* and last, the "lip clearance'' made by grinding back the ends G G of the lands, Fig. 137, to properly clear the cutting edges H H. There are three cutting edges, H, H and C: of these C is the io6 MODERN MACHINE SHOP TOOLS. least effective, as it is not a free cutting edge and grinds rather than cuts the metal. By reducing the thickness of the web at the point as shown in Fig. 138, thus making the cutting edge C short, the efficiency of the drill is materially improved. This Is of greatest value with drills of large diameter where the webs are made thick to give the necessary strength. The points may Ixr thus thinned by grinding on a small emery wheel. The flutes of twist drills as usually manufactured are cut by milling from stock of round cross section. Numerous attempts have been made to produce a satisfactory hot rolled drill, in which the flutes are formed by passing the stock which is rectangular in cross section and heated to a forging point, through spiral rolls. A hot forged drill has recently been placed on the market. In FIG. 138. , / < — ^^ [/ iV/ J /J Fir. . 139. this tool the flutes and twist are produced by forging, and great strength and tlurability of cutting edges are the claims for it by the manufacturers. In order to give the drill greater strength toward the shank, the web is increased in thickness from the point to the end of the flute. This thickening of the web is accomplished by gradually withdrawing the milling cutter from the blank as the cut ad; vances. This makes the flute shallower at its upper end, with a gradually decreasing area of cross section from the point to the shank. This contraction of the flute area prevents the free de- livery of the chips and consequent clogging of the drill. It is therefore necessary to make the flute area equal throughout its entire length. This is usually accomplished by making the pitch M the flute spiral uniformly greater from point to shank, and is DRILLS. 107 known as an ''increase twist** drill. It is also produced by giving the flute a spiral of "constant angle,** and increasing the ^idth of flute toward the shank. This latter result is obtained slightly changing the angle of the arbor carrj'ing the flute "utting mill with the axis of the drill blank as the cut advances, and the mill is receded from the blank, in giving a web of in- creased thickness. This latter method makes the lands narrower at the shank end of the flute and thereby reduces somewhat the strength of the drill. On the other hand, it possesses the ad- vantage of giving a constant angle of rake to the cutting lips as the length of tlie drill decreases. This is shown in Fig. 139, where the angle of rake is 27 J i degrees for either form of drill when the tool is new. \Mien wom nearly to tlie shank, this angle in the "increased twist** drill is materially decreased, while for the ''constant angle*' drill, it remains the same. For the small drills, the blanks are usually made from steel Fii, wire. Tliey are first cut in lengths atid then given a body clearance by filing* The flutes are each cut separately. With the drills of larger diameter, the blanks are turned in a lathe and finished to exact diameter by filing. In cutting, they are held upright in a vertical machine, both flutes being cut at the same time. The learance of the lands is made by either milling or grinding, and with the large drills both lands are relieved at the same time* Drills are given a cutting temper the entire length of the flutes, fid are carefully straightened after this process. Twist drills are sometimes made slightly over size, and after tempering are ground perfectly straight. This adds little to the j^aluc over the properly straightened drill and increases consider- bly tlie cost. Twist drills having more than two flutes ar? frequently used _for enlarging drilled or cored holes. They are very efficient for iis purpose, but as the lips do not intersect at the point, they Innot drill a hole from tlie solid stock. A three flute t\%nst drill shown in Fig. 140. They are regularly made in *^!7e« from '^ to 3 inches, varying by thirty-seconds. Th it flute io8 «0DICKN MJ drill is one having the flutes cut parallel to the axis of the dnll. anil is in other rc^^pects similar it> the twist drilL A straight fim« drill is shown in Fig. 141. In Vig. 142 is show^ a hollow drill which may \k* used to advantage in ihe drilling of dceji or long holes, the chips passing out through the hollow shank. Great care must he exercised in grinding the twist drill, as tin I'lo. 14 1, same troubles on a smaller scale as those shown in Figs, 134 an JJ5 for the flat flrill will result from the improper grinding oi the twist drill 1'he angle of \ip clearance should lie greatc at the center than at the outt-r ends of the lii)s and must not Ik excessive, as in that case the drill bites too rank. If this angle too small, however, the cut is not free and excessive heating re 1 !<;. 142, suits. The angle of the lip to the axis of the drill should bt"^ cr fiK>t. The exact taper for the several sizes is given in the follow- ing table ; also the limiting sizes of drills on which each taper is generally used: TABLE OF MORSE TAPERS. ISmallest Drill using! Largest Drill using each Taper. { each Taper, No. of Taper. Taper pet .605 .600 .605 4 .615 .695 .634 In Fig. 143 is shown the shank of what is known as the grooved shank drill to be held in a si)ecial chuck. These gRX)ves may also be applied to taper shanks. Drills are also made with square shanks to be held in ratchets and bit braces, also with shanks of various special forms. Taper shank drills are made and carried in stock by 1-64 inch sizes from yi of an inch to 2^ inches, and by 1-16 inch sizes from 2j^ inches to 3 inches. All sizes over 3 inches are special and made only to order. Straight shank drills are made by 1-64 inch sizes from 1-16 of an inch to 2^/2 inches. A regular straight shank drill is the same length over all as a taper shank. What are known, however, as jobbers' sets, running from. 1-16 of an inch to yi inch by 64ths, are considerably shorter than the regular lengths. The wire gauge sizes run from Xo. 80 — ^the smallest twist drill regularly made — to Xo. 1. The Xo. i wire gauge drill is .228 or about 15-64 of an inch in diameter, while the No. 80 is but .0135, or a little more than i-ioo of an inch in diameter* This latter drill is an exceedingly delicate little tool, having flutes quite perfectly formed. Drills are made in what are known as letter sizes, from A to Z, A being the smallest, .234 of an inch, and Z the largest, .413 of an inch. These drills are made with straight shanks. Millimeter sizes from 6 to 50 m.m. are made by most American makers. From 6 to 25 m.m. sizes increase by ^ m.m. advances. The milli- meter drills are made in both straight and taper shanks. It has not been found practical to give drills smaller than No. 74 wire gauge, .0225 of an inch, land r '^nd many driller considerably larger than this are not no MODERN MACHINE SHOP TOOLS. Practice is somewhat at variance as to the best speeds at which to run drills. The later tendencies are to reduce the feeds and increase the number of revolutions, that is for the smaller sizes. For the larger sizes, the number of revolutions varies little from TABLE OP DRILL SPEEDS. Diameter of Drills. Speed for Wrought Iron and Steel. Speed for Cast Iron. Speed for Brass. ,V inch. I7I2 855 2383 3544 ^ '•'• 1191 1772 397 565 855 ?8 '• 265 375 570 ^ " 183 267 412 |:: 147 214 330 112 168 265 h ** 96 144 227 I «* 76 115 191 1% •* 68 102 170 IX •' 58 89 150 iH *• 53 81 136 IX ** 46 74 122 i?i " 40 66 113 i^* •« 37 61 105 1^ *• 33 55 98 2 ** 31 51 92 the old practice. The above tal)le gives the speed of drills in revolutions per minute as recommended by a leading manufac- turer of drills. A rule that is easily remembered and gives approximately the correct speed is, dividing 80, no and 180 by the diameter of drill, will give the number of revolutions per minute for work on steel, cast iron and brass respectively. The results will be rather low for the smaller sizes and high for the larger sizes. The- feeds for drills should vary with the diameter of the drill and the hardness of the metal being drilled, and will usually fee 1-200 to 1-50 of an inch per revolution of the drill. In drilling wrought iron or steel, the drill should be flooded w^ith oil, or some suitable drilling compound, which lubricates the cutting edge and carries away the heat of friction. Cast iron and brass are drilled dry. A drill with cutting lips having no angle of rake will work best in brass. A straight flute drill or twist drill with lips ground as shown in Fig. 144, is well suited to this work. In drilling deep holes in steel, especially when the drill is hcM DRILLS, III in a horizontal position, it is difficult to properly lubricate the cutting edges of the drill To overcome this, oil tube drills — one of which is shown in Fig, 145 — are being very successfully used. Tn tliis drill oil is forced to the cutting hps, thus thoroughly lubricating them, at the same time helping to force out the chips and keep down the temperature. The usual method of making this drill is to mill small grooves in the lands parallel to the flutes and se- cure, by solder, in these grooves small tubes which, at the shank end, are usually made to open into a liollow in the shank from which suit- able coniTcction is made with the oil supply. One manufacturer uses the following unique method for producing these oil passages. Two small holes are drilled parallel to the axis in the stock from which the tool is to be made. The length of these holes is somewhat more than the length of the grooved portion of the finished tool, so as to connect wnth the hollow shank. After these holes are finished the stock is heated to a low forging temperature and then twisted FIG. 144. an amount such as to make the holes come parallel with the flutes pVvhen cut. A cut of this drill is shown in Fig. 146. Oil tube drills are necessarily expensive to manufacture: their I-IG. I4IJ. use will, however, frcquentiy mure tlian double the i>utput 01 the machine driving them. The drilling of holes that are tci Ix* tapped requires a drill equal in diameter to the root diameter of the tap, and is called a tap 112 MODERN MACHINE SHOP TOOLS. 1 drill. The machinist soon fixes in his mind the proper tap drills for the taps he most uses. When there is any uncertainty as lo the proper diameter, consult a table of tap drill sizes or caliper the end of the taper tap, and select a drill that will just allow the point of tap to enter ; this will give a full thread. The followinjj table gives the sizes of tap drills from J4 oi an inch to lyi inches for the V and United States Standard threads. The United State?; Standard number of threads per inch are those taken. TAP DRII.L TAHLK. Diameter of Tap. I 1^4 No. of Threads. 2o i8 i6 14 13 12 II lO 9 8 7 7 6 6 Drill for U. S. S. Thiead \ Drill for V ThrewL The location of a hole to be drilled is usually indicated by a center punch mark : if the hole must be drilled exact to this center a circle of diameter equal to the diameter of the hole to be drilled should be described about the punch mark as a center, as shown at A in Fig. 147. A few light prick punch marks should be made, O i-k;. 147. A A A A, on this circle. If the drill runs to one side as shown at B in Fig. 147, it can be drawn back by cutting away the wide edge with a cape chisel as shown at B ; this chisel cut should run DRILLS. 113 to the center. The drill must be brought concentric with the circle A A A A in this manner before it begins to cut the full diameter, as it cannot then be readily shifted. When the surface upon which the holes are laid out is a machined one, it is often better to scribe a circle about the center mark slightly larger in diameter than the required hole and drill to the center of this circle. This leaves the laying out circle on the work and readily shows any inaccuracy in the drilling. The laying out and drilling of holes in this manner when ac- curate location is necessary* requires care and skill and is usually an expensive operation. When many similar pieces are to be so drilled, it is usual to provide a suitable jig or drilling template, which insures accuracy and requires very much less time. The subject of jig drilling is taken up in Chapter XXVII. On a large amount of drilling work the hole in one part serves as a guide for drilling other holes in other parts of the work, and in many cases it is possible to use one piece of work, which has been care- fully laid out and drilled, as a template for drilling other similar pieces. W^hen the point of the drill breaks through the work and the pressure is thereby greatly reduced, care must be exercised in the handling of the feeds to prevent the drill from worming or drawing through without cutting the full circle. In case this occurs, one of three things will certainly result : break the work, the drill, or stall the machine. A straight flute drill or a twist drill with lips ground as shown in Fig. 144 will not worm through and are good tools to use for drilling thin or sheet metals. Keep the drill sharp by proper grinding. CHAITKR IX. REAMKKS. In order to produce holes as round, straight, smooth and uni- form in diameter as is required in the construction of accurate machinery, a reamer must be used. As has been shown in a pre- ceding article, the drill cannot be relied upon to produce holes l)ossessing the above qualities. A reamer is a sizing tool having two or more teeth either par- allel or at an angle with each other, the latter forming* what is known as a taj)er reamer. These teeth may be either straight or spiral ; a spiral tooth producing a shearing cut, while a straight tooth gives a square cut. As to their construction, reamers for producing parallel holes may be divided under two general heads — solid and adjustable. All taper reamers come under the solid class. A solid reamer is one having a shank and teeth made from a single piece of tool steel. The expansion reamer is a built-up tool, the usual form consisting of a shank and head, the head having suitable recesses in which are secured the cutting teeth. As adjustment to com- pensate for wear only is attempted, the amount of expansion is small. The number of teeth, their form and spacing are the important considerations in the construction of this tool. Reamers having fewer than five teeth are not to be used where accurate cylindrical truth is desired. A reamer having three teeth caimot be de- ])ended upon to produce round holes, inasmuch as any irregu- larity in the hole being reamed affects the cutting of the tool. This is shown in Fig. 148, where a depression A exists in the comes to this point it drops in, thus decreasing the cutting of C and D, and produces a hole not round. The same effect to a lesser degree is produced in a reamer having four teeth, Fig. 149. When the cut is relieved at A, the ])ressure of the cut at C will crowd the tool toward E. Since the l)ressure of cut at B and D balance each other, any decrease of cut at C causes an increase at D. and ?» and C will overbalance D. the body of the reamer moving an appreciable distance toward REAMERS. 115 E. With five or more teeth this effect practically disappears. The more cutting edges, the more smoothly will the reamer work. The construction of adjustable reamers does not admit of as many teeth as can be formed on a solid reamer, yet the advantage of adjustability to a certain extent offsets this. Reamers having an even number of teeth equally spaced do not pnxluce as good results as those having an odd number of teeth. In the former, the teeth fall opposite each other, causing greater tendencies to vibration, and in the case of reaming irregular holes, the greatest cut will be carried on two opposite teeth ; but with an odd number of teeth, the greatest cut must be carried on at least three teeth. Reamers having an even number of teeth but irregularly spaced are verv extensively made. A cross-section of such a tool is FIG. 148. PIG. 149. FIG. 150. FIG. 151. FIG 152. shown in Fig. 150. The effect is practically the same as having an odd number of teeth. The form of tooth usually employed is shown in Fig. 151. The front face is on a radial line, the flute being well filleted at the root. If an angle of rakeis given the tooth, as shown in Fig. 152, and specially so if the fillet at root is cut away, the tooth will spring out under the cut, producing an oversize hole. The grinding of the clearance on top of the tooth is an impor- tant point in the construction of a reamer. The clearance should be sufficient to properly relieve the cutting edge. If too great clearance is given, the tooth will be weak and chatter in the work. .Vs frequently produced, the cleared surface is slightly concave, the amount depending on the diameter of the emery wheel used in grinding it. As a plain surface is desirable, a wheel of large diameter which gives approximately such a surface, ^^^'^nld be employed, or better still the face of a cup emery whe< ives a straight clearance- no MODKRN MACHINE SHOI* TcX»LS. Tile an^lc of clearance will ilepend on the distance the axis of the euK-n wheel is set back of the axis of the reamer, as shewn ill Fig. 153. In no case must the wheel come in contact with ihc front face of the tootli being laffo'^ind or the one next l)ehind, and the guiding finger which steadies the reamer must alw^ays bear against the front face of the tooth being ground. When tl>c dianieler of the reamer is large and the pitch of the teeth so stnallj that the necessary clearance cannot l>e given except l>y using i<^ small an emery wheel, the wheel can be mounted on an axis at i considerable angle with the axis of ibe reamer, as shown in FigJ 154. This produces a plane surface; but due to the w*ear of tli emery wheel is not as satisfactory as the use of the cup wheel The wheel must be so placed as 10 cut its entire width, other^ FIG. T53. FIG* 154, wise it will be grooved and the cutting edges of the tooth rouofll cd off. A hand reamer is a tool ii^ir hand use : while a chucking ivixmc is operated in a machine. Fig. 155 illustrates a standanl »olid m FIG. 155. hand reamer. In its manufacture, tlie stock is first cut to leni and then turned to a diameter alntiit 1-64 inch over finish si ngtli REAMERS. 117 The flutes and square on the end of shank are next cut by milling processes. Tempering is the next operation, from which it usually comes warped to a greater or less extent. After straightening, the centers are lapped out and the reamer ground in a grinding machine to diameter and cylindrically true. All standard reamers are made .0005 of an inch over size. This is because a new reamer, l)efore l)eing used, should have its cutting edges stoned slightly. which will just about bring it down to exact diameter. If this is not done, the edges will give down a little on the first few holes reamed: so that if the reamer was made to exact diameter it would fall below size too quickly. The shank is usually ground about .001 of an inch smaller than the fluted portion, and in its use serves as a gauge to indicate when the reamer has fallen, through wear, below .001 of an inch under size. The shank should not be marred in any way, as in that case the purpose for which it was so carefully brought to size is lost, and in cases where the reamer is passed through the work, damage to the hole is apt to result. The last operation previous to grinding the clearance and final inspection in the manufacture of a reamer is the buffing out of the flutes. This is done by passing them under a small vulcan- ized emery wheel, which has first been trued to the exact outline of the flute. The hand reamers are regularly made in two lengths ; what is known as the short reamer being considerably shorter both in the flute and shank than the regular or jobber's reamer. The diameter of the point is about 1-64 of an inch under size, the tool tapering to exact diameter at about one-fourth the length of the tooth from the point. The balance of the teeth are ground nearly parallel, the diameter at the shank end being from .0005 to .00075 of an inch small. This slight taper counteracts the tendency that all reamers have to ream a hole slightly over size at the top, which is due to the tool remaining longer in contact with the wall of the hole at the top than at the bottom. The limit of error allowed in their manufacture does not exceed .00025 of an iiKh. When, for the parallel shank of the hand reamer, a taper shank is substituted, the reamer becomes adapted to use in a drill press or other machine. The form and length of flute is the same as for the regular hand reamer, except at the point, where the teeth instead of tapering for one-fourth of the length of the flute, run j^arallel to the point. This form is used because the reamer cv ii8 MnDRR!^ MACHt.SR SHIIP ttfOLSi casi.*r and faster, and as it is steadied by the sptmUe, no difficulty is experitMiceil in starling ii true. In Vig. l>(* is shown a spiral nutcd reamer T1ie\ are aluji\> FIG, 156. cut with a left-hand spiral They give a smooth shearing mt and] are specially valuable for machine reaming i>n centers as they d*fl not tend to draw^ into the work and off from the center. They are| also tnade in shell and taper. Fig. 157 illustrates a fluted chucking reamer witli taper sliank. Fic;. 157, The total length of this tool is approximately the same as thcj length of a hand reamer. The leelh arc short and slightly taj>eredl at the point, which facilitates starting when used against the ^ dead center of a lathe. It is also made with straight shank. The rose chucking reamer, Fig. 158, is of tlie same length and FIG. 158. V provided with the same forms of shank as a fluted chucking H reamer. The head is grountl cylindrical with cutting teeth on H the end. The circular flutes do not form cutting edges, their uiBce H being to carry the luhricants to the point of the tool, and, espe- H cially when used in a horizontal position, to carry aw^ay the chips. H Tt is therefore important that a flute he provided for each cutting H lip. The ficad is given only a slight clearance in its length. The H result is that holes produced with the rose reamer are usually H^ round and straight, but not so smooth as those formed by longe 1 nc lually ^ >ngerB REAMERS. tT9 cutting edges. The lack of clearance in this tool makes il unsuit- able fur reaming tlcep holes, as a small amoimt of heat causes it _to expand an amount sufficiciu to hind in the hole reamed. In Fig, 159 is shown a three-flute chucking reamer. These FIG, 159, reamers have the shanks and fluted portion ground cylindrically rue and are specially adapted in tlie reaming o( deep ♦'< inch |>er fix^t are in all respects similar to the taper pin reamer shown.] When a saliint is called the ''guide" or the "pilot" point, and is usually ground .005 to .007 of an inch under size, which of course limits the amount of stock left for finishing. This reamer is made from }i of an inch to 2j^ inches in diameter^ and is strictly an ex- ^■bansive reamer. ^H A form of Morse adjustable blade reamer is itltistrated in Fig, ^H65. It consists of a suitable number of blades or chasers, fitting FIG. 104. FIG, 165. FIG» 166. filled slots and abutting against a ground tapered plug in the enter of the headj the enLS. lower collar. A reamer of this class witli steep taper to the, lx)ttom of the grooves and long threaded portions can be adjiibte for several size-s. This, however* is not considered good practice the adjustment [x^ing simply to maintain one size. This adjust^ ment, however, is great enough to allow for several regrindings. Those classes of a^ljustahlc blade reamers in which each blade is set out independentty should be reground after each ad*^ justment^ as it is almost impossible to set the blades out equally, . In using the reamer it shuultl he turned continually forward^ both on the advance and on the witlidravval. Turning it backward while in the work is quite apt to injure the tool, due largely ta small particles of cuttings lodging lietween the clearance surJ faces and the wall of the hole. In hand reaming the tool cam usually be passed through the work. Oil should be used freclj in reaming steel or wrought iron. Cast iron and brass are usually reamed cIr^^ A small amount of nil will, however, frequenllyj improve the quality of the work in these metals. The preparation of the holes for taper reaming is of great imJ portance. As a reamer should not ri*move all the metal thai! would be left if a drill the size of the point of the reamer were passed through the work, several drills (»f diflferent diameter may be used, producing a stepped hole, as shown in Fig. 167. H V FIG. 167* the work is done in a lathe, the taper attachment or compnur rest can be advantageously used, using a boring tuol to enlarge the drilled hole. If the lathe has neither of these attachmemd the hole can be stepped out, as in Fig. 167, with th^ boring toolJ A roughing reamer, b*ig. 168, is well suited to the jireparation ot a hole to be taper reamed* FIG. 168. REAMERS. I2J A simple form of reamer shown in Fig, 169 will frequemly obviate the expense of a special reamer when only a few holes are n to be sized. The tool can he made at slight expense, and when ^fcarefuUy constructed will produce very good results. ^H The taper pipe reamer, Fig, 170, is a roughing reamer of ^Ktandard pipe tap taper for sizing a drilled or hored hole hefore tapping with pipe tap, I The reamers used for reaming CL-nter bearings in work to be L.^„ Hartford reamer with one cutting ^ilgi:. it cannot be relied I upon to produce a true conical hole. A "new Hartford*' center i reamer is shown at Tj. It has three cutting edges, and will pro- duce a true hole. These reamers are intended to follow a small drilled center hole, and are made with 60-degree. 72-degree and mo. 169. nil FIG. 170. 82-degTee angles, 60 degrees being the standard. They are also made in several sizes from V4 ^^ ^i of an inch, largest cutting liameters. A form of combination center reamer and drill, in liich the drill and reamer blades are held in a suitable shank, is shown at C. At D is shown a cumbination center drill and reamer that has come into general use. It is admirably adapted to lis work, being efficient, simple and inexpensive. Tlie drill steadies the reamer, which makes it cut smoother, and insures its coming central with the drilled hole. This is of special value wlieii the surface of the work is uneven. The countersink is sit lar lo the ct-nttT rv^^anier, \mvmy;, however, a greater number a|| teeth. When reainhigf either taper or parallel in a lathe, the wur rotatinf^ and the reamer held against the dead center, true work nnist not he expected, if the reamer is allowed to follow directljj after the drill as it is practically impossible to so start a drill ihn the drilled linle will he exactly concentric to the axis of the lath< spindle. This will cause the point of the reamer to move in small circle around the center of the rotation, producing a tapere instead of a parallel hole. If true holes are required, tlie drill riG. ITT. used should be enough smaller than the reamer to allow for l!t^ truing (if the hfdir with the Ijoring to*jh which will bring it conJ centric with the axis of rotation before the reamer finishes it tc exact ne- receive the tap wrench. This shank is frequently turned to the exaa diameter of the root of the threarl, and used to f;:auge the final settings of the single pointed thread- ing tool, with which the thread of the tap is finished, it having heen previously roughed down with a chaser. This work is done 111 a lathe having an accurate lead screw, the accuracy of the tap iiefK-nding largely upon this screw. Hand taps are made in sets, three t^ps comprising what is known as a tap set. These are called the taper, plug and bottom- ing, as shown in Fig. 176. As manufactured by the Pratt & Whitney Company, the only difference between these taps is in the form of the fxjint. They all have the same thread parallel at the root, and if passed entirely through the work will produce similar threads. The taper tap is parallel on the point for a dis- tance equal to one-fourth the diameter of the tap. This point is made the diameter of the roots of the teeth, which is the correct size of the hole to be tapped in order to produce a full thread. The teeth at the shank end are parallel for a length equal to the ing hales in niacccssible places. The stay-boll tap, as shown in Fig. 179, is a combined reanii and tap, ui»ed hy boiler makers for reaming and lapping the hol€ for stay-bolts. The taps arc ma arc oftc widely separated, and must be tapped tngelhcr. as otherwise tH stay-bolts will noi enter ihe seamt! plate wilhuut springing tl plates a fraction of the pitch. These taps are sometimes mad as lon^ as five feel. They run from three-quarters to one and on^ half inches in diameter. A hub, or master tap, is one used for cutting the threads dies. Fig. 180 shows a hab for cuiiiii pipe dies. The pipe tap shown in Fig. i8i fidl teetli to the point, the standard pig taper being three-quarters of an inch ]% foot. The following tabic gives ill num!>er of threads per inch and tap dril^ fur standard pipe taps: ami ft S mm n FIG. 178. FIG. 179. 3 Fta. 1S0. FIG. 181 SCRI'W TIIRKADS. TAPS AND DIES. 133 Diameter of Pipe. 1 Number of Threads. /S 27 k 18 H 18 H 14 H 14 I iiYz i> ".\< 1'2 ii>. 2 ",'2 2>i 8 3 8 3)2' 8 4 8 Tap Drill. If 3 A 3iff 4A In case a pipe reamer is not used for sizing ahead of the tap the holes may be drilled 1-64 inch larger for the small sizes and 1-32 inch for the large sizes. Fig. 182 shows a machine or nut tap. It is provided with a long easy taper on the threaded portion and a long shank some- what smaller in diameter than the root of the thread. .\ combination drill and pipe tap, shown in I'ig. 183, is in quite general use. It is a valuable tool for drilling and tapping gas and water pipes under pressure. ' A collapsing tap is one in which the teeth or chasers, after cut- ting the thread, are carried tow-ard the center enough to allow them to clear the threads so that the tap can be removed without hacking. This not only saves time, but the wear on the teeth incident to backing them out of the threaded hole. A form of col- lapsing tap manufactured by the Geometric Drill Company is shown in Fig. 184. The mechanism is such that when the two side stops come in contact witL the work the lead or draw of the tap releases a clutch in the head which unlocks the mechanism and the chasers are in- stantly collapsed. The setting of the stops determines the depth of the threaded hole. The chasers are then expanded again and locked in position for the next operation by means of the handle shown on the body of the tap. A graduated adjustment provides for slight variations in the diameter of the tap. The advantages of the collapsing tap over the solid lies in the saving of time due to being able to allow the machine to run continuously forward, thus saving the time required with the solid tap to back out. The backing out not only injures the lao 134 ifcmciizK Stic TOOLS. btit ift quite apt chatting slightly to in/itrr the thread* Again, the p<>$sibiltty iii thr iltamttcT uf the tap is frrcjiicntly i>f valued A ttiiiite^l nuinhcr of iliffcrttit ^ize> may lie lapped with each !ii2c of head by sulisiitui- ing diffirrrni sc- quentJy brittle. They give no wartiing before tlic) !»reak. therefore care and jut%ineiit niii'^t Ik- exercised in their iise. in nsing hans, a wrench which fit^ closely the square irti the shank, anri ha%*in>; rTppfi^ite handler of equal !englh, should Ik* us. Tile puH on the handles ^hmild l»r tinif three teeth, so that these teeth do the most of the cutting, the following simply sizing. If desired to cut a full thread close u^ to a shouldiT the die is turned over. lender the second class we consider first the screw* |)late, shown in Fig. 188. This is a thin plate of tempered steel, in which FIG. iSS. FIG. 189. number of holes of varying diameters, threaded w^ith diflfcre pitches and (jruvided w ith opposite notches to fcirm cutting edge have l)een produced. It is a primitive tool, suited only for w^or of small diameter^ where correct threads are not required. Dies of the second class arc usually made adjustable to cor pensate for wear. In Fig. 189 is shown a form q( dk Ur^el^ u^ SCREW •niHEAUi>, TAPS ANU DIES. U7 for small sizes, one-sixteenth to one-quarter of an inch. It U riven a spring temper at C. and is held in a wrought ring, not fehown in the figure, A small set screw passinj^ thruii^h tlie rini; and engaging the notch shown in tht- die edge, serves lo spring the die i«»gether, when through wear it becomes over* Fig. n;n ilhi^^trates tlie Grant adjustable die. in which tlie four tha?!ers are held in a cast-iron collet surrounded by a wrouglit ring. The chaser?* are beveled off on the outer ends, which en- age with corresponding l>eveled grooves in the ring. By forc- ig the ring down, the chasers arc moved toward the center. The FIG. 190. rioiint of adjustment in this die is one-thirty-second of an inch. The chasers are numbered* with corresponding nuniberi^ on the ide of the grix>ves in which they belong. This prevents the pusHi- ^ility of putimg together incorrectly when the chasers have been noved for grinding. This die is sharpen<.'d by grinding back the front face of the [lasers. They should be ground only a short distance back of tie toolh rcxAf so as not to interfere with the bearing in the >llet. In Fig. 191 15 shown the lightning adjustable die. The r us*^' in a nmchinc and where smooth, accnrate tlireatls arc dcsiretl should lie used in pairs, one for rougliing and one for finishing. A clamp collar fitted over the end of the die prevents its spreading. This form of FIG, 192. die can be sharpencfl hv passing a thin emery wheel through the j grooves. Self-opening and adjustable dies are for machine threading ver\^ generally used. The advantages are the same as for the collapsing tap. Fig. 194 illustrates the Geometric Drill Com-j SCREW THREADS, TAPS .\SU TilKS. 139 pany's self-opening die. This tool is usually moimted in the turret of a chucking^ machine or screw machine. The chasers are set up for the cut by turning the head until the mechanism locks yiL,. 193, them into position. Pulling forward on the chasers unlocks the hfad and a «?pring: throws thf dies out. In operation the die is moved forward over the work until the end of the thread is no, 194, reached, w^hcn In stopj^in^ the carrfaj^e the forward lead or draw of the die unlocks it and the chasers spring open. Ily means of tile two screws and graduations shown on tho I40 MODERN machinp: shop tools. side of the tool a micrometer adjustment, which controls all the chasers, is. quickly made, thus making it possible to make a tight or loose fitting screw as desired. The die head shown is provided with a roughing and finishing attachment controlled by the small lever at the back. In using this attachment the chasers are held out for the first cut over about i-ioo of an inch, which is taken at the second cut. This is necessary only when extremely uniform and accurate threads are required. The chasers may be very quickly removed for sharpening or changing from one size to another. r\)r pipe threading opening dies are very extensively used. The advancing edge of the die chasers in all forms that produce a finished thread at one cut, is chamfered off for two or three teeth, which divides the cutting duty and facilitates starting the thread. The die should not be run bottom side up on the v/ork, as in that case the first tooth does nearly all the cutting duty. Only in unusual cases is a workman justified in this procedure. Oil should always be used liberally on the tap or die when cut- ting steel or wrought iron ; a little oil on the tap when cutting cast iron or brass makes it run easier and does no injury to the thread or the tool. Sperm or lard oil is best for this purpose. In threading steel or wrought iron by hand the tap or die should, after every two or three turns forward, be given a slight turn back. This facilitates the removing of the cuttings and allows the oil to find its way to the points of the teeth. Xo matter how accurately a tap or die is cut the hardening ])rocess will distort it somewhat. If this distortion followed any fixed law, allowance could be made in the threading that would offset this variation, but as the distortion is variable, even when the conditions are the most uniform possible, it is difficult to make allowance for it. As a general thing the taps contract in length, thus decreasing the ])itch, and ex])anding in diameter. A die of standard diameter must not be used to thread stock that is one-thirty-second of an inch oversize, as the strain on the ond IPIG, 195, Fu;. 196. FIG. 197. le bottom of the shank or mnrti>sc through the shank, and the lot shoold be but slightly wider than the thickness of the tang. This gives the tang a good bearing well dow^n toward its base, i^he slot must be sufficientl}" long to allow the taper drift or ey. shown in Fig. 198, to be inserted over the end of the tang to force the drill out. If the shank or bearing in the socket is jainmcd, the former will not enter the bearing the proper depUi, the tang will catch on the point, the frictional drive between shank and bearing surfaces will be decreased and a twisted or liroken tang will usually result. Frequently, in twisting, tang will force the drill tnit of the s€>cket an amount sufficient allow it to turn in the hearing, the tang cutting nut the •irJe of the slot at the Twttom and thus ruining the scxrkei. In iMg. iijLj is show*n the new Cleveland drill socket and drift. The design of this socket is to prevent the hattering and ujisetting of the drill tangs, the drift seating squarely upon ll end of the tang as shown. When sockets are to he fitted to «ipindle or turret beannig having other than u Morse taper, they may be obtained witi FIG. 199. rough shanks, whicli can he Lurned to the desired size or tap Such a socket is sliown in Fig. 196. When it is desired to bush the hearing in the ch"ill spindle socket to a smaller size, the bushing or sleeve shown in Kig. ic is used. It is the same as the socket » except the shank is mad to envelop the bearing, thus decreasing the length of the coii nection* Sleeves are not as convenient as sockets when tl|j drill is to be frequently removed, as it is necessary to remo< the sleeve before tht drill can be forced out. In such cases IIKILL AND TA HOLDERS* best to bush the spindle beariiig to ihe size larger than rhc drill ':ipt:r, and then use a siKket for, the last reduction. In Fig. 200 is shown a sectional view of the Cleveland grip ■re* FIG. 200. ket. The object of this socket is to provide a stronger ^rive for the drill, and thus avoid the twisting of the tang. A key-way is milled in tlie shatik of tJie drill, into which key A of the socket is forced by rotating the collar through about one-fourth of a rcvuhilion. The collar is 'ecessed as shown at C, the recess being eccentric to the socket* W hen the collar is turned so that the deep part of die recess is opposite the key, forcing the drill out crowds the key hack out of ay. When the key- way is properly milled, the key su fits it that e drive is entirely removed from the tang. This makes it sible to use drills which have had their tangs twisted off. his collar and key. when applied to the end of the drill press lindle. will hold the drill from worming into the work and pull- ig out of the spindle when the point of the drill strikes through, will also prevent boring l)ars from pulling out of the bearing hen used for under-cutting, a feature appreciated by those who ve much of this kind of work to do. When the taper shank drill is to be used in the lathe for \\'ork chucked pieces, the holder shown in Fig, 201 is excellently FIG. 201. Adapted. It is virtually a sleeve having a long handle attached, bliich may be allowed to rest on the carriage of the lathe, the hank end of the drill l>eing steadied on its own center against 146 MODERN MACHINE SHOP TOOLS. the tail center of the lathe. *\nother holder for this purpose, Fijj, 202, is made in which a center in tlie holder is used rather thaa the drill center. In Fig. 203 is shown a sleeve holder in which the sleeve is kept from rotating by means of the two screws, whic have points turned to fit the slot in tlie sleeve. Another form of lathe socket is shown in Fig. 204. Hy inu- ting a bar through the round hole it may be used between cemcrs^ and becomes similar to the holder show^i in Fig. 202. It is, how^ ever, usually used in the tail spiudle bearing, the outside taj PIG. 20a. being the same as on the dead center. \\ hen so used ii id mucli safer than when used between centers, as the drill or reamer it holds cannot pull off center. The holder used for driving the (jraham grooved shank drill is shown in Frg. 205. It is made in fuur sizes, holding from 2}4-inch drills down to 3-32-inch drills. By means of reducersj one of which is shown in the figure, small drills may be held ill tlic large chucks. These holders are very compact, being bu| FIG, 203. little larger in diameter than tlie common socket. As the gtcnn in the drill are cut parallel with each other, taper shank drill may be grooved to fit correctly in these holders, which, as with the socket shown in Fig. 200, makes a good method for reclaiming' drills that have lost their tangs. The above are all positive drive holders, which, in the case ol DRILL AND TAl* HOLDERS. 147 idden stopping of the drill will break it if the madiine does not stall. To overcome this, numerous friction drive holders have been devised, one of the best being shown in Fig. 206. In this holder the socket A is he!d bv friction between the end of the PIG. 204. FIG. 205. FIG. 206. 148 MODERN MACHINK SHOP TOOLS. shank G and the collar B. F F are fiber washers between the sliding surfaces, which gives a smooth motion when slipping occurs, and enables the operator to more easily adjust the tool to the proper grip. The collar C forms a lock nut to presence adjustment. Tlic bushings E, which carry the drills, fit in A, being driven by two keys. In its use the collar B is adjusted up until the friction will just nicely drive the drill. This tool, which is made in two sizes, is provided with the necessary bushings for holding drills and taps up to iVi inches in diameter. Although bushings for holding the ordinary square shank taps may be had, the tap with special shank as shown in the figure is best adapted to use in this holder. In machine tapping, and especially where more than one size of drill is to be used, much time may be saved b\ the use of this holder. Take, for example, the drilling and tap- jMug of engine boxes, where two drills are used, one the diameter of the stud through the cap, and the other the tapping sizefor the stud. Each drill is placed in a holder, E. The changes from stud drill or tap drill and to tap are made by slipping out the one holder and putting in another, all of which may be done with- out stopi^ing the spindle. Another form of friction tap holder is shown in Fig. 207. In this holder the upper half of the clutch is keyed to the shank, the lower half turning free on the end of the shank. The jaws of \he clutch are beveled on their edges, the spring, which is readily adjusted for tension, holding the halves in contact. When the drive on the tap becomes too heavy, the Ix^veled edges force the clutch halves apart, thus allowing the machine spindle to rotate without turning the tap. The friciional drive tap holders shown in Figs. 206 and 207 require a reversing spintlle machine in which to operate them. In I'ig. 208 is shown the "Star" lapping attachment which contains a reversing mechanism, thus adapting it to tapping work on ma- e:;i!K- without reversible spindle. As with the others it is pro- vi'li'! with an adjustable friction drive which can be adjusted to t;.'- rt.<:i:ired tension to drive any size of tap the tool w^ill operate. l:\ its o|>eration.the lx)dy of the tool is held from rotating by s :j':::cr the chain shown to some fixed |)art of the drilling ma- i.'r.ir.i:. In driving the tap forward the upper spindle, which is ir.dcpen'*^ ' *' tower, is engaged with the lower by allowing tlv idy to engage the clutch, which is keyed to lock with the lower. The upper bevel gear DRILL AND TAP HOLDERS. 149 Tins idle on the upper spindle. When the tap has passed through \\v wurk ur bottomed as the case may he, raising the drill- ng spindle first disengages the clutch from the lower spindle* knd then clutches it with the upper gear, thus driving the lower ipindlc through the bevel gears in the reverse direction at an in- creased velocity due to the increased ratio in the gearing. When number of holes arc to be tapped to the same deptli the *^top IG. 207. no. 208, FIG. 209. tiown is used. When this stop comes in contact with the surface )f the work, the body of the tool stops and the tap and its spindle iraws away from and disengages the clutch. A slight upward riovement of the driving spindle engages the gears and the tap hacked out. The *'Presto*' drill chuck. Fig. 209. is a positive driven holder provided with an assortment of drill sleeves NV'\\k\\ mac^' W ^- ISO MODERN MACIilXE SHOP TOOLS. cured in the liolder without stopping the rotation of the tnacf spindle. The skrves are driven by a tang and held in |XJsition by two pins in the body of the holder which engage the groovcl shown in tlie sleeve. The collar, wiiich rotates upon the body of] the liolder, when down locks the pins into the groove and whenj held up allows the pins to throw back, releasing the sleeve. marked saving in time is effected by the use of holders of thisJ character on work requiring various sizes of drills especially whenj the drilling machine is provided with but one spindle. Straight shank drills must be held in drill chucks, of which there are a large variety on the market. In Figs. 2T0 and 21 1 are sliown two well-known chucks for this purpose. They are exam- ples of the two general classes, Fig. 210 showing a chuck in which tlie jaws have a radial motion, and Fig, 211 one in which FIG. 210. the radial motion is due to another motion along the axis of the chuck. Chucks of the class shown in Fig. 210 are made in sizes ta hold from o to 2 inches, while those of the class shown in Fig. 21 ^| are not made beyond J-i^inch capacity. The drill chuck shown in Fig. 212 is regularly made in two sizes holding drills to Yi inch. It coitsists of a shank, sleeve nut and taper split bushings, Tlie bushings are hardened and hold hut one size of drill, separate bushings being required for each The compactness of this chuck makes it a very convenient size. tool for light work. By using a split steel sleeve parallel on th ittside and tapered to fit the drill shank on the inside, tap ank drills may be satisfactorily held in the parallel jaws of th 1 chuck. In the Pratt chnck, a bar throu^U iKe cKwck l\a& DRILL AND TAP HOLDERS. ISI rectangular hole, which receives the tang of the taper shank drill, thus making a positive drive. In using drill chucks, it would be well to bear in mind that the keys and spanners furnished with them will grip the jaws suffi- ciently tight upon the drill without the assistance of a 12-inch monkey wrench or two feet of gas pipe. Overstraining a chuck destroys its accuracy. Always remove a chuck from the spindle FIG. 211, I the same as you would a drill or socket — with the drift. Don*t eel that because it has a large hub you are expected to knock 1 out with a hammer. Before inserting the shank of a drill, socket or chuck in its bearing, wipe both surfaces to free them of oil and dirt, thus making them hold better and preventing injury to the surfaces. FIG. 212. Hln using the drift, a light upward blow on the underside of the ^Bouter end will usually stan the drill easier than a heavier blow ^"on the tnd in the direction of its length. The solid tap wrench, an example of which is shown in Fig. 813. is provided with one or more square holes to fit the squares the end of the taps. The principal objection to the solid tap vrench is that each hole will properly fit but one size of X52 MODERN MACHINE SHOP TOOLS* shank, thus requiring a nntnber oi vvrcnclies to meet general re- 1 quircments. W hen riiore than one hole is made in tJiis wnnchj the handles become of unequal length when using any but thej central hnle. winch results in an unbalanced pressure on thej oppnsne sitles of the tap» producing a transverse «train, in the] resistance of which the tap is weak. Good judgment on the parti FIG. 215, of the operator will, however, enable htm to balance these pre?^ sures, Again; the tendency is to Ui^t! these wrenches on taps tlie^ squares of wfiich are too small to properly fit in the holes, thus | rounding and twisting the tap squares. In Fig. 214 is shown an adjustable tap wrench. These 1 •(i encEN Hiveii FH., 2T4. 9 wrenches adjust to fit a wide range of sizes. Of the particiilari wrench shown, five sizes take all laps from the smallest to I i • inch. The flies forming iht* squares are carefully hardened and' fitted in the body of the wrench, thus preserving a true square. FIG, 215. which fits nicely the square on the tap to which they should be L closely adjusted, The T-han'ecn the two may be quite clearly defined. A mandrel is designed to] carry work that is to be operated upon by a cutting tool, while! on the other hand the arhor carries and drives a cutting tool, ail with the milling machine and saw arbors. Mandrels may be classed under tw^o heads, solid and expand- ing. The solid mandrel is made slightly tapering, in order tlui it may he forced to a tight fit in the bore of the work. The amount of this taper varies with the class of work the mandrel is to be used on, it being hut shght at the most, A bar of common round iron or steel centered and turned^ to the required diameter const ittites the mandrel in its stmplestfl form. Such a tool, as is usually found in the average jobbing shop, is shown in Fig. 216. It is hardly worthy the name man-^ FiG. 216. drel, and although a solid one might fairly come under the ex^ panding, or rather shrinking class, as it is brought down by turning and filing to fit the bore of every new piece of work that comes along. It has one quality, however, that can always b^| depended iii>on, and that is imtruth. With mandrels of thb clas^^ accurate results cannot be expected. Since a mandrel must be rigid, it should be as short as the nature of the work will permit, and made of as stiff a materia^ as possible. Its centers should be carefully formed, and th4l body finished cylindrically true upon them. The centers, at least, should be tempered or case hardened, to prevent their wear^ Ti out of true. In Fig, 217 is shown the correct construction fo^l e end of a mandrel The end for a letiglU about ec\jxal to tHe MANDR£LS. 155 diameter of the tool is reduced slightly in diameter and provided with a flat on one side, against which the screw of the dog or driver is set. As the dog is very apt to mutilate somewhat the ends, this reduction in diameter is quite necessary. Since the accuracy of the mandrel depends so much 011 its centers, it is necessary to protect them as much as possible from injury while forcing the mandrel into the bore of the work. This is best FIG. 217. accomplished by recessing the ends around the center bearing as L^jshown in the figure, The angle of Uie bearing should be 60 de- ^krees, with a small hole drilled at the bottom. The object of this ^Hrilled hole is to prevent strain being thrown onto the delicate ^^■point of the machine center* and to form a small oil reservoir to ^^id in lubricating the bearing. ' In Fig. 218 is shown a hardened and ground steel mandrel. ^^These tools are made for general shop work, the length increas- Hing with the diameter from 1,1/4 inches for a V^-inch mandrel to 17 inches for a 4-inch. These lengths are, of course, arbitrary FIG. 2X8, and may for special uses be materially increased or decreased. ^^\s manufactured by the several makers, these mandrels differ ^■but little in length and details of design. They should be made Hpf a good grade of tool steel, carefully hardened with the centers ' lapped true after the hardening, and the body ground cylin- ^^drically true upon these centers, it being rotated upon stationary ^gOT dead centers for this last operation. [ When the greatest possible accuracy is required it is sidered best to make these mandrels of tot ' ''annealed steel, with the ends only hardened. Thi' 'm the 156 MODERN MACHINE SHOP TOOLS. that the steel if hardened throughout changes somewhat in form and receives temper strains, which, although relieved in the grind- ing, does not allow the tool to immediately take its permanent set. lH)r this reason a mandrel that has been hardened throughout should be first rough ground, leaving a small amount for final finishing. This finishing should not be done for some time after the rough grinding, thus allowing the tool to season and to acquire permanent set. The set will not be appreciably altered if only a very small amount is left for the final finish. Hardening makes the mandrel stiffer and less liable to surface injury than in the case of the unhardened one. It is not, how- ever, for the purpose of allowing careless workmen to run their cutting tools into its surface with the idea that it will not be injured thereby. Cutting tools are usually made of a higher grade steel than the mandrel, and often tempered harder, in which case the mandrel suffers if the tool comes in contact with it. These mandrels are usually tapered about one-hundredth of an inch to the foot, the diameter being exact at the center. The size is stamped on the flat at the larger' end. They will fit holes reamed with standard reamers, although the taper prevents uni- form grip on the work at the two ends of the bore. In forcing these mandrels into the bore, good judgment must be exercised, as they constitute a wedge, which will produce enormous pressure if forced too har(l, resulting in bursting the work if hard and brittle, or if soft in permanently enlarging the bore and giving it a taper corresponding to that of the mandrel. The use of the hardened and ground mandrel does much toward the preserving of uniformity in the size of holes, in the work of shops, where these tools are used. A hole only a few thou- sandths of an inch under or over size prevents, in the first case, the mandrel from entering, and in the latter allows it to fall through. Its slight taper makes it a good comparative gauge by means of which minute differences in diameter of bores may be compared by the relative distance to which the mandrel enters. Expansion mandrels, while possessing the decided advantage over the solid ones of a parallel grip in the bore of the work, have too often the disadvantage of complication of parts, which makes them unsuitable for the most accurate work, and especially so after they have become somewhat worn. These objections, hoWever, "an hardly be said to exist in the case of the mandrel shown in 'g. 219. This mandrel consists of a cast-\Tox\ V^v\%V\vcv^, VvaNvcv^ -a^ MANDRKLS. 157 tapered bore, wliich fits accurately the taper of the mandrel. The bushing, which is gnmiirl externally, parallel and lo exact tliain- eier. is split partly through at two points, and entirely througli at a third, thus allowing' for a slight expansion when the mantlrel is driven in. Three bushings varying hy sixteenths for the smaller and eighths for the larger sizes may be used on each size of man- drel The taper used is K inch per foot, the hearing surfaces lieing accurately ground- It is cvitlent that the allo\val>le anii>unt of expansion is small, yet sufficient to grip firmly in an accurately 219. sized hole. An attempt tu expand this hushing in an oversizetl btile would result in cracking it ; a thing that would happen before the bushing, due 10 its expansion, would throw the mandrel ap- preciably out of true. Tile bushings are regularly listed from ^ inch to 3'H inches in diameter, requiring eleven mandrels for the complete set. The expanding mandrel. Fig. 220, consists of a hardened and FIG. 220. ground mandrel with four splines milled at an angle with the axis, four jaws and a containing hand of seamless drawn steel i inches two sets of jaws are furnished for] each mandrel and above zy^ inches three sets. The mandrel of Fig. 221 consists of three stepped jaws, caps- ' ble of end motion in three splines. %vhich are milled in the l>ody 1 of the mandrel at a considerable angli! with the axis. Tfie head] A, which moves over a parallel portion, E, of the mandrel isrJ recessed at C to receive the notched ends of the jaws, ihusj holding them in ibc same relative position. In oj>erating. iht* jaws are moved to the small end of the mandrel, the work placed FIG. 221. on the proper step and the mandrel forced through, the jawi expanding -to the bore of the work. This tool is made in fourj sizes, fitting all bores from >li to 4 inches. When it is necessary to face a piece of work that is being] driven on a mandrel close down to the bore, the expanding type«ij as shown above, have the advantage over the solid mandrjel, ^incc the work can lie left projecting slightly over one end of the bush or jaws, which allows room for the cutting tool to pass over the edge of the bore. Frequently it becomes necessary to machine work, the bor« 7i wfiich is otficr than cylindrical, on a mandrel When thcl rcross-section of such bores is circular, a cone maiulrel can be iisedj to advantage. Such a tool is shown in Fig, 222. It is strictlji a special tool, as its range of adaptability is small U is neee>saryl that the faces, A A, of the work be machined at right angles ic the bore before placing on the mandrel as otherwise the worii MANDRELS. 159 will not be held concentric with its axis. The coning bush, B, may be shrunk on, pinned or threaded to the mandrel, and C should be keyed and backed up with a nut. These bushes should be turned in place on the mandrel centers. For mandrels of large diameter the form shown in Fig. 223 is frequently used. Here the draw bolts, A A, two to four in number, take the place of the nut in the preceding figure. As be- ^^^^^^ VIG. 222. FIG. 223. fore, one disk is secured to the mandrel and the other keyed but capable of motion over it. In Fig. 224 is shown a kink in mandrels that for some classes of work can be used to advantage. As with all tools of this class it should be reasonably well made, accurately finished as to diameter and parallel. A short piece of round drill rod serves for the roller which lies in a milled groove that is a few thousandths of an inch deeper at the back than the diameter of the roller. In FIG. 224. FIG. 225. operation, the first start of the work to turn wedges the roller be- tween the slot and the wall of the bore, holding the work firmly from turning. A slight backward turn releases it, and the mandrel can be slipped out without pounding. The bore of the work must fit the mandrel exactly, as the slack is all taken up on one side, which will throw the work out of true if loose. This mandrel would not be suitable for work on which the pressure of the cut was in the direction of its axis, as in most milling and planing be- tween centers. l6o MODERN MACHINE SHOP TOOLS. When the bore of the work is threaded, the mandrel must be provided with a thread to fit the bore, and a radial face, against which the work screws to a stop. This is commonly known as a nut mandrel, and in its simplest form is shown in Fig. 225. Work that is to be finished on this mandrel should at the timt of threading, if possible, have one face turned at right angles to the bore, so that it may seat squarely against this face. This, however, is not possible when the work is tapped, as is the case with nuts. Since, for rapidity of manipulation, the mandrel should not fit the thread of the work too closely, an untrue seat cocks the work, and it is not faced squarely. The ball seat face of the mandrel shown in Fig. 226 overcomes this difficulty very nicely. In finishing round, smooth machine parts on a screw or nut mandrel, they usually tighten under the pressure of the cut so firmly against the face, that it is difficult to remove them without FIG. 226. FIG. 227. injuring their finish. The mandrel shown in Fig. 22^ is a valuable tool on work of this character. The collar A forms the bearing face F and is keyed to the mandrel, the spline allowing it to slip back when the nut R is slacked, and thus relieves the pressure between F and the face of the work. By using a finer pitch thread in R than the mandrel thread, C, or a left-hand thread in B, when C is right hand, the collar may be omitted. This makes a cheaper mandrel, but is not so good, as the nut and work lock so firmly that considerable force is usually necessary to start the former. When the work is to be faced the threaded portion of the mandrel should be somewhat shorter than the thickness of the work, thus allowing the cutting tool to reach the tops of the threads in the bore without injuring the mandrel threads. A stub mandrel is one used in the end of a piece of work, as shown, for example, at A in Fig. 228. These generally fit a tap- ered seat, and are special in character. Mandrels will usually drive the work by friction. If the work is large in diameter for the size of the bore, it should be driven, MANDRELS. l6l if possible, from a point near the circumference, independent of the mandrel. A mandrel the surface of which has been oiled slightly, will drive nearly as well as if dry ; and the chances of abrasion, in case of slipping, with its certain injury to tool and work, materially decreased. Mandrel center bearings are often made too small to wear well, as the intense pressure between the machine center and the bearing prevents proper lubrication and increases the chances of breaking off the center. A shallow trench, cut to the point of the machine center on the top side, improves the chances of getting oil to the bearing and does not injure the center, the pressure on it being generally from the under side. When rotat- ing between rigidly clamped centers, the slight expansion of FIG. 228. FIG. 229. the mandrel, due to the heating of the work, will frequently increase the pressure between centers and bearing sufficient to 'force out all lubrication, and cause abrasion of the surfaces, which is certain to ruin the bearing. This trouble is most likely to occur when the work is rotating at a high rate, as for filing or polishing. This bearing should, therefore, be of liberal size and well lubricated. Since the value of a mandrel depends largely upon the con- dition of its center bearings, it is very important that they be carefully protected from injury in driving. Nothing harder than a copper hammer should be used on the mandrel ends. A babbitt hammer or raw-hide mallet is preferable. If these are not available, a block of tough wood, end grain, must be used under the common hammer. The mandrel block shown in Fig. l62 MODERN MACHINE SHOl» TOOI^, 229 forms a solid support for tlie work whiL- the tnandrel is being- j driven in or ant The Ijcst practice dispenses entirely with driving and presses' tlic mandrel iJiio the bore. A press designed ff.r tbl^ pnrfMi^e is shown in Figs, 230 and 23 1 , The smaller press. Fig. 230* is for light work, lian*^ling man- drels up to I'i inch in diameter. It is arranged to clam[) to ihc : bed of the lathe or on a bench. For the heavier work the press] shown in Fig, 231 is suitable, It is mounted on its own column and provided with an adjustable knee. The plunger and lever are cuunier-weighted and a ralchel lever adjustment provided on th pinion shaft. When the lever is up the pawl is disengaged and tHd| plunger can be quickly adjusted to any required height by turning the hand wheel A lead pad on the base of the column prevents in- jury to the mandrel should it fall in pressing out. The kx)p shown prevents the mandrel from falling on its side* With these presses mandrels may be forced squarely without injury to them or the work. I «t1 ^^tnijit CHAPTER XIIL THE LATHE. Thai most important of all machine tOols» the lathe in ii3 everal forms, nam rally comes first for our consideration. The _reat variety of work that can be jjer formed on the lathe, and Ihe efficient way in which it is done, are the conditions upon |which its importance depends. The young mechanic, when com- FIG, 232. naMcr in the lailte, as u^e<\ in general work, will have Flearncd nearly all the principles involved in the operating of thf other classes of ordinary machine tools. For special work the lathe is so modified to meet the parti- cular conditions that its identity is almost lost. For example, the turret latlie, the screw machine, the pipe threading machtne, the cutting- off machine and even the vertical boring mtJI are all UH mm MACII inodifications of the lathe in which the principle of routing iTi work lu a statiunary ciitlinj]^ tool is c^irriecl out* The sp€fd, or liaod laihc, an example of which is shown ia Fig. 232 is the simplest form of metal turning lathe. It is sinjjie geared lathe which means that the cone is secured to thd spindle, the nimihef of changes in spindle speed depending up the number of steps on the cone. The tool rest is adjuMab^ in all directions, hut not provided with feeds* These lathesJ when provided with foot-pfnver mechanism, may be driven bf the operator. They are, however, usually furnished with a couni tershafl and driven from some other source of power. Tlie lianij lathe is used for all classes of turning operations in which a hand tool is used. They are also used for drilling, filing and polisli infT rotating work. When used larfjcly for drilling* the levt operated tail stock spindle, as shown in Fig. 253. is of value. lU FIG. 233. it provides for a quick movement of the spindle and is more senstJ tive than the wheel and screw feed. In the tail-stock shown the spindle, screw and hand-wheel are mounted in a quill which fit$ the bearing in the body casting, A segment of a gear pivoted tlie hack of the body casting engages a rack cut on the quill^ Turning the segment by means of the lever moves the iprill an' strains to which it is sulijected* It should be proiH*rly fitted to the inner shears and clamped in place. The live sjiindle and spindle bearings are the most iniponanl elements in the lathe» as the accuracy of the work produced depends very largely upon the accuracy of the spindle. It should l>e cylinrlrically true, accurately fitted in its bearings and its center of mtatit ti exactly parallel with the shears. The threaded nose and center l>earing must be exactly concentric FIG. 235. FIG, 2],6. with the bearing part« of the spindle. The cone should lie given a nice bearing fit on the spindle and the back gears properly cut and pitched The feed antl screw cutting gear should he reliable and powerful The head-stock of the lathe shown in Fig. 234 illustrates the general form as used in double geared lathes. The live spindle bearing is usually made of bronze or gettu- ine Babbitt metal. When the latter material is used it is, after beitig cast in the casings peaned sufficiently to fill out any shrink- age as well as to intensify the metal, after which it is bored, reamed and carefully bedded by scraping to an accurate fit on tbe si)indle. The Babbitt bearing as used on the lathes by the F. E. Reed Co, is shown in Fig. 255. In order to reduce the wear to a minimum the spindle bearings should be large. Pro- visions for taking tip the wear are, however, always neces- sary. The end thrust of the spindle is usually taken at the end bearing, an adjustable thrust screw receiving the pressure. The TtIK LATHn. 167 modern engine lathe is usually provided with a hollow spindle. I the size of the hole often heing as large as the diameter of the Npindle will safely permit. This is frequently a point of great value in working up stock that will pass through the spindle. All back-geared lathes may he run as single geared lathes by locking the cone with the spindle gear. The purpose of the Track- kear is to reduce the speed of the spindle and correspondingly increase its pull Thus, with a five step cone running single geared, five changes of speed can be had, the speed reducing an^j > 4()-j(» 3-80 or for the 25 revolutions of the cone in the former exaiiipk' the spindle would revolve 25 X 3-80 = 15-16 of one rt vohitiun. In large lathes performing very heavy duty, the application of the power to the circumference of the face-plate steadies the cut and removes the excessive torsional strain that wouM Ix^ tlirowii upon the spindle if all the power was transmitted throiij^di it. TIk' tail-stock, or foot-stock, as it is frequently called, ^ accurately fitted to the inner shears. It can be moved along the I If.. .»;^7. PIG. 238. •iH'.ir, .m«l rlainpr«l lirnily to tliem at any point. The function ni I Ik I. Ill vhK U Is In ('any ihc tail or dead spindle. This spindle ht-. II ^ In-.iiiiii; rl«t>rly. ran I»e moved in or out through a con- Most or clamp. This forms the most rigid rest, it having but the mic gibbed joint. The raise and fall rest is shown in Fig. 241. It Kio. 241. FIG. 242. is a form oi elevating rest. In Fig. 242 is shown a compound re^i. This fi>rni. while not as rigid as the plain rest, has become vcr\ |H>pnlar among machinists, lKX\iuse of its points, of con- vmiciuc li has the regular automatic cross-feed and the anxiliaiv tVcil which can he operated at any required angle with {\w ^piuillc. This latter teed for the larger lathes is frequently nuulc anioniaiic. Tlie manner in which it is accomplished by the rmnani .Machine l\>nipan\. on lathes from 22 to 42 inch swing is shown in I'ii;. J43. Here the splined cross-feed screw carries a sKevc. which. ]\\ means o\ an ivcentric o|>erated by the handle ;m the left, can he chnched with (Mie of the four bevel gears that transmit the nuniiMi to tlie nut. The sliile rest shtnvn in Fig. J44 is for use on speed lathes as shown in Fig. 2^2 for light turning work. It may he clamped in anv ' '^n on the IhhI. It is provided with hand THE LATHE* m feeds only, and as the slides are mounted on a f^^adnated base it may be set at any desired angle for taper turning. In alt engine lathes the carriage is moved over the shears by means of the lead screw or the feed rod and their connections. _The former constitutes a positive drive without possibility of fffi miii]umi5mi'i FIG. 243. itppage, while the latter is a purely friction drive. The in- Idependent feed rod is frequently dispensed with in small lathes, md the lead screw made to do its work. In such cases the lead Bcrew is splined and the feed mechani^^m is driven from a collar ^iiich has a feather engaging the spline and slides over the lead FIG. 544. ?w. As the feed is engaged by means of a clutch this also Pomis a friptional driver. The feed rod is driven by belt aiid provided regularly nith irce changes of speed. Since it is frequently desirable to have 172 MODERN MACHINE SHOP TOOLS. feeds finer or coarser than these three changes can give, it is now quite cuinmon to provide either a change gear connection with the feed rod as shown in Fig. 245 or provisions for connecting the feed rod with the change gear mechanism of the lead screw as FIG. 245. shown in Fij^. 246. In Fig. 245, by changing places with gears A and H, or substituting others any desired speed of feed rod C can 1)0 ()!)taine(l. In V\^. 246 when gear E is in dotted position the feed rod is driven l)v belt in the usual manner. When, how- i: ^ I n: Pq 3L 30 FIG. 246. ever, chnnp^c-gcar feeds are required E is in position shown and is driven by tiie gear D which is secured on the sleeve A and receives its motion through the change gears F and B. The clutch G, which slides over a kcv In the le^id sct^^n l^, k dls- THE LATHE. 173 engaged from the sleeve A, thus preventing the lead screw from turning while the feed is in operation. As the carriage must be capable of feed in either direction, a change in direction of motion of feed mechanism must be pro- vided for. This is usually accomplished by interposing an idle gear either in the mechanism of the apron and allowing the feed rod to rotate constantly in one direction, or in the head-stock gearing. The latter is the more common method, inasmuch as a change in direction of lead screw rotation is necessary and that cannot be accomplished in the apron. In Fig. 247 is shown the arrange- ment of gears usually employed. Gear A is secured to the spindle of the lathe. When A gears with B, the direction of rotation of the feed cone is as shown by the arrow. B and C rotate on studs secured in a plate which turns about the axis of D. By throwing the handle H down and C into mesh with A, B becomes in- 1^ FIG. 247. FIG. 248. operative and the direction of rotation of D is changed. The stud G also carries one of the change gears E. The diameter of gears B and C is immaterial, inasmuch as they are simply idlers between A and D, and do not affect the velocity ratio. When gear D is of the same diameter as gear A the stud and spindle have the same rate of rotation. D is, however, frequently made smaller than A, giving the stud a higher rate of rotation. The mechanism shown in Fig. 248 is frequently employed for reversing the feed in lathes and other machine tools. The feed rod C carries two bevel pinions B and E and the clutch D. D slides over a key in C and engages either E or B, both of which run loose upon C and mesh with the bevel gear A. When D and E are locked the rotation of A will be as shown by arrow, B turning free on the shaft, and when B and D engage the direction of A is reversed. 174 MODERN MACHINE SHOP TOOLS. The lead screw is one of the most important parts of the lathe, as accurate screw threads cannot be produced with an inaccurate lead screw. The builders of first class lathes use great care in the production of their screws, the lathe used for cutting them being provided with a carefully cut master screw which is used only for the cutting of lead screws, used on that lathe. The wear on this master screw is therefore very slight, and as soon as the lead screw shows signs of inaccuracy the master screw is sub- stituted and a new lead screw for the lathe cut. In this way the standard of the master screw is very closely maintained. The lead screw drawls the carriage, the force being applied at the nut. It is. therefore, best to take hold of the carriage as close as possible to the shears and thus avoid the tendency to cramp the carriage. In the lathes manufactured by the American Tool ot 3- n KIG. 249. Works ("onipany, the lead screw is p'laced inside the shears, as shown ill I "ij;. 240, in such a manner as to get the most direct pull on the carriage. The lead screw nut is made in halves usually of brass and so mounted in the apron that it can he readily closed onto the screw. In order to cut threads of different pitches with the same lead screw a set of clian.t2:c gears must he provided for the lathe, so that the advance of the screw, carriage and tool per revolution of the spindle may be exactly etiual to the pitch of the thread beinc^ cut. In iMg. 249 is shown the common arrangement of chancre gear, generally called a single gear. Gears .\, D, and E. an::-!. a coar or ^^^o teeth would be required on the screw It m gears I an«l P.. In like manner if 70 threads were 10 be out _ \ S-70 --- S- 140 = 4-70. as ratios between stud and screw - J- 10 \ j-7. which would cive 15 and 75 teeth for one pair and 20 aii'l 7(> teeth f.-r the otlu r pair. \vy pair « f trear-^. in which the teeth have the required ratin. rr.a;. i^ :i>e'l. it *^i course being desirable to so select the change g( ar< that the greatest possible number of required pitches may 1h. cut wirh as small an assortment of change gears as possible. In ' rder to avoid the time lost in changing gears where lar^^fo THE LATHE. 177 varieties of different pitch threads are to be cut, several builders have brought out lathes in which the change gears are all mounted, a change from one to the other being made by a simple lever movement. In Fig. 251 is shown this class of change gear mechanism as applied to the Hendey-Xorton lathes. It will be noticed that the change gears are all mounted on the lead screw and that the auxiliary shaft A is driven through the gear mechan- ism from the spindle at a fixed velocity ratio with the spindle. Gear B is an idler mounted on the shifting lever and communi- cates the motion from A to any ^ear on the lead screw. In this manner twelve changes in pitch may be obtained without chang- ing gears and for each change in size of gear on A twelve more pitches may be cut. In this particular lathe the reversing mechanism of Fig 248 is applied in the head as clearly shown in cut. By a suitable com- bination of levers the operating of the reverse is controlled by a lever in the apron thus allowing the work to run in one direction all the time. In a mechanism of this character the gears must be rigidly mounted and accurately cut and pitched, as otherwise in such long trains the spring and back lash is excessive. The form of thread usually used on lead screws has sides of about 15 degree angle, as this form allows for taking up the wear in the nut by closing it onto the screw. The United States stand- ard thread is not well adapted as the steep angle of its sides forces the nut, which is necessarily made in halves, apart. The lead screw and nut should never be used for ordinary feeds as the screw would soon lose its accuracy through wear. Unfortunately for the accuracy of the screw a comparatively short portion of its length usually does most of the leading for threads cut in the lathe, and as a result that portion becomes worn and inaccurate while the balance remains in good condition. The size of a lathe is commonly determined by its swing and the length of the bed, the swing referring to the greatest diameter of work, when held on the face plate or in a chuck, that the lathe will turn over the shears. Thus, an 18-inch by 10 foot lathe means one that has a bed 10 feet long and will swing work 18 inches in diameter. The builder usually allows from yi to Yz inch over the rated swing, thus making is possible to actually finish a piece of work of the same diameter as the normal swing of the lathe The swing over the carnage and greatest (WsXawc^ ^ -^-^^iTv 178 MODI'ZRN MACHINE SHOP TOOLS. THE LATHE. 1 79 centers are also important dimensions. The former is usually from one-half to two-thirds the normal swing of the lathe. The lathe should be well and accurately built, of ample weight, with operating parts conveniently arranged. Weight is desirable and usually indicates a first-class tool. This is not necessarily true, however, as frequently a badly designed machine will have certain parts excessively heavy with other parts correspondingly light, the whole often making an unusually heavy machine — not so good as the lighter machine in which good judgment on the part of the designer has led to proper proportions for all the parts. . Lathe builders carefully test the accuracy of their lathes be- ^ fore sending them out. As it is frequently desirable for the me- chanic to test his lathe as to accuracy of alignment, or in making repairs on lathes that have become inaccurate through wear, the following methods, commonly employed for this purpose, may be of value. To determine if the center bearing in the live spindle is axially true with its spindle: Turn up, on accurately ground centers, the test bar shown in Fig. 252. The shank S should fit the center bearing nicely and the collars A and R should be exactly of the same diameter. Place the test bar in the live center bearing, leaving it unsupported at the outer end, and cause the spindle to rotate. If the outer end of the bar runs perfectly true, then the bearing must be concentric with the spindle. By using the test indicator Fig. 105, the exact amount of the untruth, if any, may be determined. To test the parallelism of the live spindle and the shears: If the center bearing has been found exactly concentric, place the test bar in the bearing as before. Put a fine pointed tool or scriber in the tool post and so adjust that it will just touch the top of the collar A. Now move the carriage until the pointer is over the collar R. If it touches it with the same degree of contact as on A, the spindle must be horizontally parallel with the shears and line of motion of the carriage. In like manner test the front side of the collars A and R w^th the scriber, and if as before the degree of contact is the same on both, the spindle must be ver- tically parallel with the shears. To test the carriage cross shears at right-angles to the spindle : Take a very light cut over the large face plate and test with a standard straight edge. If perfectly plane, the alignmeut Is cor- i8o MODKKX MA( IIINK Sllor TCX)LS. rect. If the face plate is perfectly true and it is not desirable to lake a cut over it, a smooth ended tool held in the tool iK>st can be brought up to the face of the plate, near the center, just close enough to pinch a piece of paper lightly. Now move the rest out t(^ the outer vd^t; of the i)late without allowing the tool or carriage to shift along the bed, and if the paix:r is still pinched to the same degree the alignment must be correct. Assuming the face plate as true lK)th on its face and circum- ference, to test the alignment of the tail spindle: Make a stid) A to fir the tail spindle bearing as shown in Fig. 253. Bring the FIG. 252. =mL=^^ i'i<- 253. •^])in(lle l)ack until the tail >dV\\ starts to cxpel the Stub center A. and M) adjust the- screw that when A bears against its point a smooth turning tit between A and the spindle bearing results. C is an arm i)assing through A and secured by the thumb screw !». I) is a j)ointer which ])asses through the arm C and is held by the Ihiunb screw I. Adjust the point E so it touches the upper surface of the circumference of the face plate at G. Next swing the arm around until point E comes on the lx)ttom of the j)late at J. If E touches at J with same degree of pressure as at G, then the tail spindle must be at the same height as the live id in like manner if it bears equally on the two sides c the cross adjustment must be right. THE LATHE. l8l In order to determine whether the center lifie of the tail spindle is coincident with that of the live spindle we can reverse the point of D and bring F into contact with th^ face of the plate at H. If it maintains uniform pressure of contact while the arm C is revolved entirely around, then the dead spindle is cen- tral and parallel with the live spindle. If the tail spindle has been set over for turning taper and it is desired to bring it back central, first set it as near to the correct position shown by the lines as possible, then place a long bar ])etween centers, similar to the one shown in Fig. 252. and take a very light cut over the collars A and P> w^ithout changing the transverse position of the tool. Caliper the diameters of A and r> accurately. If they are not alike, make another set-over adjustment of the tail stock and repeat, continuing to do so until they caliper exactly alike. Two trials will usually be found sufficient. To test the truth of the live center, place a bar between centers and turn a small portion up as close to the live spindle as the dog or driver will permit ; then reverse ends with the bar and test the turned spot for truth of rotation. If perfectly true the live center is running true. The centers in the test bars should always be carefully reamed and lapped or worn down to true surfaces. It is difficult to keep the lathe centers in good condition and accurate work demands that they be so kept. The dead center must be true and hard in order to wear well. The live ceiUer need not be so hard, inasmuch as there is no wear between it and tlie bearing in the work. The live center should be ground in ])osition by means of a center grinder. After being ground the live center should be removed from its l)earings in the si)indle only when absolutely necessary, as it is practically impossible to ])ut it back and have it perfectly true. A small prick jnnich mark or the nose of the spindle and a corresponding one on the ceiiter will enable the operator to put the center back as nearly as ])()ssible in its correct position. It is advisable, where nice work is to be done, to always grind the live center after it has been re- moved. Tl'e center should always be ground to an angle of ex- actly ()0 degrees. CHAITKR Xl\ THK LATUK IS MOUIKIKD FORMS. In Fig. 2$4 h shown the Pratt & WliitTiey lo-inch tool-nuk^**! lathe; a toul sipcciully tlt?signt' ;k inch, stt'iJ ami coniliinalion chucks, and a cuinpj set uf lurning^, tlireading and knurling tools. In many shi*ps, and especially those dohig a line of jobbinj work, it frequently hecomes necessary to turn a piece of worl too large for ihc largest lathe in the shop. The tiine-honorei practice in cases of this kind is to use a sel qC tiaki^vcv^ Hocks uttd* mH^^ TUE LMUB IN M Pr>RMS. >83 hciid and tail stocks of the largest swnisj lathe in the shop* These blocks are planed tugcthcr and to fit the shears, thus giving the same elevation to both stocks and proper altgntnent. The McCabe two-spindle lathe is a tool desi|^ied to meet these conditions. ,\ front view of this machine is shown in Fijc 255 and a rear view in Fig. ^56, The general construction of the Sll ^tK^l is quite clearly shown in the cin^. The |f>wer ^(fiindlrii v*Mt slitutc a standard 2*>inch engine lathe siuitahk- fur all w^rk Omt ould ordinarily be performed on such a lathe. By |»lftcni^: llu linion shown in Fig, 255 un the m^te of the Inwcr '•iHndlr >Mid le large internal geared face plate on the upper xpindlr a ^H iruh triple*geared lathe is obtained. The elevating t.iol block *hnwn takes the place of the compound rest when Ufing the upper npindlr, i84 MonKKN MACHINE SHOP inul^. A ven wide heavy bed is useil, extemlinj^ well out iinderi jSCts of spindles. T\w up]>cr spindles set back of the lower odcs» irhich with a short extension on the front of the carriage cross sliear allows the tool to be set sufficiently back from the center to operate correctly upon tlic largest work the upper spindle will swing* Still another form of lathe intended for the occasional turning j of vv closed and 321/2 inches with gap open. The con-j stnic!irk. When equipi)ed with box turning tools, hollow mills, >elf- mlng dies and cui-oflf slide, it becomes well adapted to rod "work on steel and brass, A tapered stop pin locates the turret jemral with the spindle, and a tempered and ground index ring Ivides exaaly the rotation about the vertical axis. Other forms of carriage turrets are shown in Figs. 261 and That of Fig. 2tt2 is arranged to carry common lathe tools order to preserre settings^ on duplicate work. i88 MnUKRK MACHINE SHOP TOOLS. In Fig.. 263 is shown an engine lathe witli an automatic re- volvinjt,^ turret on llie shears; and a friction back gear. The lumt is provided with aiUtmiatic fceil aciuaied by an rTMle]>endem tVcd rod at the back of the bed- The turret is usually operated by a V*e« - - tnmjiitiU* as shown, the mechanism heinj,' such thai the head tP miatcd ihroLij^h one division h\ the lu^^t pijrtinn of the slide's stroke in carry inpj it hack from the work» Tliis arrangement of FIG> 264. THE l-ATHK IX MODJFIKU FORMS. iutret leaves the carriage free for operations upi:)n the work simultane*3Usly with the tools in i\w turret. In Fig-. 2(>4 is shown a plain tttrrct machine. 'I1u^ turret is hand rotating and hand feed. The usual hand-operated cross- slide for cut-off and forming tools is provided. This constitutes ^he turret machine in what is tennecl its simplest form. As a large percentage of lathe work is held in the chuck and quires only short tCM>l travel* classes of lathes for this character of work, with shnrt beds titled witli turret hfads atid kiinwu as monitor and chucking lathes, are madf. Fig, 265 illustrates a jnitor lathe. The turret sli(!c is operated with a lever or rew^ and provided with a cross adjustment for facing. A FIG. 265* suitable stop on the cross shear enables the turret to lie readily rought back to a ceiUral pK)sition. These lathes are made either ^th or without back gears. Fhe inclined chaser head» which irries an inverted tool used for forming, boring and threading, carried on a rigid chafer bar ^mounted on the rear of the ?d. The bar slides endwise and also rotates in its bearings, _thus allowing the head to lie turnerl back out of the way when Dt in use. For thrcatiing purpt^ses. the end of the chaser ar carries what is known as the *' follower/' which engages the ircaded *' leader'* shown at the left of the head st(»ck. The ader may be of any desired pitch aiid need not he long, as the daracter of the threads cut does not re([uire it. As many of the tireads cut in a lathe of this class are pipe threads. sr>me pro- p/on must be made for cutting them \ \vv vW t^id 190 MOIIEHN MACinXK SHOl' TCM>I^. ack gear without stopping, being the form quite generally used. An automatic oil pump supplies a 1(X)tl of oil for hibricatinf^ the cutting irx)ls and carrying away the heat. The automatic screw machine* an example of which is showTi in Fig- 267, is a machine designed for the automatic production of machine screws and a large variety of small work that ca cut from the end of bar stock. All r ^nts are cntirff Iij2 MdlHCRX MALJIINE SHur TOOl-S. automatic and controlled by quick-moving cams. All dead movt mcnts, as the setting np of the stock, the return of the turret $M and the rotation of the iiirrct, are made very quickly by ihaftd running at cotisiani speeds and irrespective of the sp the work movements. In Fig. 26S h shown a view 01 ih^ tlxsKoK mm* THE L.^Tin: » ■raai lathe. This is a ^ _ _ prodticiti^ large qgantkics of di^ficair «^ort^ A bemT> ct\*« carriagtr ood indiaed mnm afte aMBAMl «■ Ae \ operations arc brj^dr ptitutwiiJ b^ kmomA-b/BcA Hmks^ hcM the CTi^ss carriage aod tbe bcsra^ aad f^tber inn*rmil bv tools mooDiefl in the reirvt, Bm^mg^ m At mo&c ot spindle are oset! tur stradirB^ the l««K tef^ A!^ ^^^ * oitters are pnc>vkkd nitli tankned jedi} gfuuwl [pilots, which fit hnshings m the ctiudk s|»dlr. or «^irks I steadying the icW and addk^ lEiudi ici its cfficlcocv, Tbe^ I are re^buly equipped with taper attachmnit^ atvi erating upon chiicketl work that is to Ik pro- luced in duplicate. In this tool iwu turrets, one a borinj; and lacing turret, the other a turning turret^ are mounted uix»n a revolving plate in such a manner that either niay be brought into jpcration as desired. The machine is equipped with a lever [>]>erated scroll chuck, which pcnniis of put ling in and renmving vork witliout stopping the spindle In Fig, 270 is ilkistratcd an antMinatic chucking inachine, [This machine 15 flrfij^nrrl ffi perform aTitmnaticafly the several t4>]H.Tations r it variety of chucked l^ork. Til' rciiinred only for chucking ind truir-- ft is therefore possible [for one i As with the automatic [•screw n c made at very quick speeds. iiniJKkX MAC In rig, 2j\ is showTi the **tUttiirret" !atlk\ a tool specially] adapted iv tlic rapid proilucium of a great variety of work cu% Xrom bar stock. The capacity of the machine is 2 inches in I ^ KIG. -*70. Fltt. 271. diciiiK'tcr hy J4 inches long, the arrangement of ihe tools on tl flat turret being sucli as to allt'w the work to pass througll] disitance nut exceedint;^ 24 inches. THK LATIIK IN MCJill I'rKU TORMS. In Fig, 272 is shown a top view of the turret, showing the tools in place. The hearing of the turret, which is gihbetl at its outer edge, is large, flie tools do not <)verhaiig and are -consequently very rigid. The automatic chuck used on this mo. 272. machine is shown in section in Fig. 2y^, It is shown in the closed position. lU moving the outside collar to the right the jaws are released, and the work hy means of an ingenious roller feed is advanced for the next operation. The chuck jaws may be removecd rests upon a three- point support to prevent twisting wlien standing on an uneven foundation. Many valuahle features characteristic of the other tools hy its builders enter into the construction of this lathe. The pipe-threading machine and cutting-off machine are FIG. 273. lACHtNR »HOl» roots. Special forms of turning lathes designed for their particular class ul work* The accelerated speed cutiing-uff machines are upcr- ated by a variable drive su arranged that as the cutling-uff blado approach the center uf ilie bar the speed of roiaiion iiicrcascji and thus maintains a nearly constant cutting speed from ontsirlc t»' center uf the work. i Lathe countershafts, and in fact all machine tool coumoH shafts, are important adjuncts to the machine which unfortu^ nately do nut always receive the proper amount of thought on the part of the designer or care Jn their construction. Many ex- ccllent tools are sail out with inferior counier*iliafts, and as iliey * 1^ sa , . PIG. 274. are quite apt to W- neglected by the user, especially in breaking il they very soon give trouble. The boxes should lie self-oili and tbf loose pulleys provided with means for proper hibricati \\ hen tight and loose ]>ulleys are used, il is desirable to have the loose pulley somewhat smaller in diameter than the light* th relieving some nf the belt tension when on the loose pulley smootli* reainc'd pulley bore and a smooth*finished and careful! fitted shaft will, when properly oiled, give desired result Clutch ])ulleys esjiecially for reversing ctnuitersiiafts are much' used. The\ should be simple and admit of proper lubrication and adjustment. he I il, m^ m^ m^ Jltwrto. CHAPTER XV. LATHE TOOLS. On the subject of cutting tools for the lathe we will consider only the more general points, as practice alone can bring out the details of proper form and setting. The common lathe tool as shown in Fig. 275 is a short bar of tool steel of rectangular cross section having a cutting edge formed on one end by forging and grinding. The cutting edges FIG. 275. must be hardened and tempered in order that they may properly cut the metals upon which they operate. The form of the cutting edge depends ui)on the kind and hardness of the metal to be cut, the amount of metal to l>e removed and whether the cut is tn be a roughing or a finishing one. These tools wlicn new aft* made from six to twelve inches long, their length depending FIG. 276. riG. 277. upon the size of the lathe in which they are to Ix- used. As the c. as a lathe tool, of no further value. The cutting cd^e of the lathe tool, as slviwn in Fig. 2p>. h:u^ 198 MODKRX MACHINK SHOP TOOLS. what we term an ang^le of clearance A and an angle of rake H. The angle of clearance has the greatest strength value, as the smaller this angle the greater the support given the cutting edge. 1^'or facing, the tool must have some clearance as otherwise the cutting edge is held away from the work. On cylindrical work if set somewhat below the center, it will clear the body of the work but will not properly clear the feed. The greater the angles of rake and clearance the more acute will be the cutting edge and the finer and smoother the cut. If the edge is too acute, however, it will not stand up to the work properly. The angle of rake has the greatest cutting value, as strength of cutting edge prevents excessive clearance. A tool may have front rake as in Fig. 278, or side rake as irr Fig. 277. It is usual, however, to grind it with both front an'l side rake as shown in Fig. 278. A tool without rake requires FIG. 278. PIG. 279. greater force to drive it through the cut as it tears rather thair cuts the metal. It does not leave a smooth surface and springs the work unduly. VoT general practice the angle of clearance should be small, only enough to properly clear the cutting edge, from 5 to 15 degrees usually being sufficient. The angle of rake, on the other hand, should be as great as the character of the tool and hard- ness of the work will permit. The small clearance angle gives good support to the cutting edge and prevents its dipping inr«.) the work. The large angle of rake gives keenness to the cuttinj;^ edge, making a tool that cuts smoothly and free. For these acute cutting edges the temper cannot be too hard, as in that case the q(\^c chips off. As the hardness of the metal operated upon increases, the angle of rake must be reduced and the hard- ncss of the cutting edge increased. U\THE TOl>I^, Ii» The above does not apply to the working of brass, as that metal should be worked with a tool ha\nng sliglu clearance and no rake. For the same rate of feed a tool operating u^x>n work of small diameter must have a greater angle of clearance than is necessary when used on work of lai^e diameter, as the same feed gives a greater pitch angle in the former case. This is clearly shown in Fig. 279. It is always desirable when a heavy Out is being taken to have that part of the cutting edge presenten when the angle of clearance is excessive and tb^ nq edg'/ set high above the center. In general a tool works best when set for h< \y above the center. When above the center tool or work causes the tool tr) dip into the initriw surface. Soft «"^« in the metal or 200 MODERN MACHINE SHOP TOOLS. cut will increase this trouble. As the spring comes from the tool post block and points below the cutting edge, setting the tool down to the center of the work reduces but does not over- come this difficulty. If the tool rest was perfectly rigid then a tool having its cutting edge dropped to a line even with the bottom of the tool at point of support would, owing to its own deflection, swing out rather than into the work when set at or below the center. In all cases the tool should be held as firmly as possible and well back in the tool post. In setting a tool for a heavy cut it should when possiWe be set raking back rather than ahead as in case of its slipping m the tool post it will swing out of the work rather than into it. This, of course, cannot be done when it is necessary to take the cut close up to the dog or driver. Cutting-off tools work free and smooth when given a small amount of top rake. As with other tools, however, when used on brass they should have no top rake and will frequently be found to work better with a small amount of negative rake. The boring t(X)l as commonly forged from bar steel is shovn^ in iMg. 281. The diameter and length of the stem depend upon the size and depth of the bore in which the tool is to be used. This tool is necessarily a springy one and should, therefore, be as short and heavy as possible, thus requiring a large assort- ment of sizes for any range of work. Tiingstt-n or self-hardening steel has come into quite general use for lathe tools. It is an **air hardening" steel, and after forging must be kept from water. .\s it is '*hot short" it is ex- ceedingly difficult to forge int(^ any other than the most simple forms. Its great value c^ver ordinary tool steel lies in its hard- ness and temper-holding, (juality. which makes it possible to use higher cutting speed without injury to the cutting edge due to the heating. It is several times more expensive than the best grades of ordinar\ tool steel, and for this reason and also on account of the difficulties met with in forging it, numerous forms oi holders for its efficient and economical use have been introducetl. In all such tixils only the cutting portion is of the self-harden- ing steel, the holder being a drop forging of mild steel. The cutting portion is (^f such form that it can be kept in proper condition for work by simply grinding it, thus avoiding the ex- pense of forgini^. In Fig. 282 is shown an Armstrong tool holder of this class with slta\v;\A\. \>oA\. \\ \s ?\sc\ vcv^^^^ ^^^^'^ LATHE TOOl-S. 20I »t steel used will not cunduct away the heat as will the larger iKxly in the forged to*»l. For thi$ reason il is always advisable to use as large a holder any job as its nature and the size of the lathe will permit, -Vn inserted blade cutting-off tool by the same maker is >wn in Mg. 284. In tools of this class the blade is securely FIG, 284 amped in the holder and may be extended an amount just suflS- "cieru to make the re<|uired depth of cut, thus insuring the maxi- mum strength of Idade in ever> case* The lilades are carelul!> ground to thickness, given the necessary clearance and sharpened^ hy grinding from the end and top. 20P MODERN MACHINE SHOP TCK)US. The Hill bent cutlinp:-off tool shown in Fig. 285 is a simp atitl relialjle fool. The blade h firmly hcltl in the holder by th clamp bolts shown. The blades are of self -hardening steel. FIG. 2R5, A modification of ihi.s toul as shnwn in Fi^s. 2W1 and 2%j' has made a unir|ne and substantial side-cutting tooL These took are made right and left hand. They have self -hardening blades and should be ground mostly FtG 2B( from the end the side and top j^rintlin^ JCiving the clearance an^ rake. They are a very satisfactory sulis^titute for the fori^ed ^ifi tool on all classes of work. The Miniirst rintj-cutting to^-^l. Pig. 28R* is a box holder FIG. 287. which two cntting-off blades may be held, Ily using distanc blocks between tbem. rin^s nf an\ width within tlie cafiacitv LATflE TCIOLS. 203 the tool may be cut to uniform width. The first cutter is usually set slighily in advance of the second and serves more as a g^uide than a cutting tool, h is frequently desirable to convert the first blade into a side-cutting^ tool and let it ^ve a truing cut over the edge of the rin^ and ahead of the cutting-oflF blade. The tool shown in lig, jS<) h one of the several patent tools which meet the requirements of a first-class boring tool very »fc->^^* • -f^^9,. ■,',.. j'.yy ->.^ FIG. 290. nicely. The stem whicli carries a small cutting point 01 self- ■ hardening steel can be extended for any rcqvurcd depth of bore rithin the limits of the tool It is providetl with two cuttcr- 3lding tips as shown. At A anle tool to forge, is a difficult (one to grind and get correct in angle, clearance and lead. The patent threading tools that can be ground without changing their form have as a resuh come into very general use. The [>1 shown itj Pig. 292 has a bent holdrr with a cutter, capable MODERN MACMIME SHOP TOOI-S. of rotation, attached to it. The cutter is correctly ground in iti| angle anri is sharpened hy radial fn*i^i*hng on the top of ifel cutting surface. The upper portion of the cutter h scrratcdJ allowing the set screw together with the clamp bolt to hold ill firmly in position. The form is such that the angular surfaces! iippri^jach the center as the culling face is ground hack , thus tnain-J KIG, 2y2. taining proper clearance. The i)lane of the cutter h slightly in <: lined from that of the holder, to accommodate the tool to Ui average lead of the pitches cut, The Pratt & Whitney threathng tool, Fig, 293. has a straigh cutler correctly ground in the angle and firmly clamped in t!;t holder, (hit- ctirner of the cutter is provided with threads whic tfugage the ihread;^ on the small lockiug screw show*n* Tlti l»IG, 293. cutter is ground from the top face. The offset cutter shown the figure is used for cutting close up to a shoulder. This holdd is also usefl for holding chasers and formed cutters of variou outlines. The Rhodes square-threading ltx»l, Fig. 294, is a form of U holder for the cutting of square threads, 11 lades for any di «^! pttch of thread to be cut are clamped as shown. The form. ^^M the hlar surface work. In Fig. 298 is shown a forming block and formed cutter. rhis tool is securely bolted to the carriage block or cut-off rest. le cutter is firmlv attached to the block and is of sudi a form VIC. 298. as to produce the required irregular outlines. The top of the cutter should be at the height of the lathe spindle. A swingin.^^ cui-oflF tool is usually attached, as shown, for cutting off the stock ifter it is formed up. A box milling tool or turner is shown, front and back view. in Fig. 2iyg, These tcM^ls are secured to the turret. They consist no. 299. 208 MODERN MACHINE SHOP TOOLS, of a hardened adjustable back rest and holder in which the i cutting tool is secured. The t^ol and holder mav be adjuslrl [ for obtaining proper depth of cut. The holder in this tool maty A b\ means of a cam and lever, be thrown back when the tol rcniuved from the work, thus preventing the cutter from scratctt-j ing the finished surface. A painting box tool is shown in Fig* 300. It is designed l^rj pointing up or crowning the end of Ijar vsork. In Fig. 300 A is shown an adjustable lathe or box mill Tliil PIG. 300. ■^tool is carried in the turret and works over the end of bar st The cutters are mounted in such a manner that they niay be justed to turn an\ iliameter within the range of the tooL 'l*hc cutters cut from the end, the inner portion serving to guide antl steady the work. In setting to a required diameter the cutters 1 may he set down onto a standard hardeneins rather than the dog. As the dogs abt>ve shown depend on a screw to hold them se- curolv ow the wi^k. care nuist be exercised or the w-ork is verv CHICKS AND DRIVERS FOR LATHK WORK. 211 apt to be injured. The screw should always have a hardened fiat or oval point. While such a point does not hold as hrnily as the cupped point, it does not cut into the work as badly. When used on finished work a ferrule of sheet brass, or preferably, copper should be put on the work under the dog to prevent any FIG. 303. [•IG. 304. injury to the work surface. The screw should be tightened <.»nough to safely drive without slipping. If the dog slips it is respectively. Fig. 305, are ex- cellent. These dogs are very nicely made of forged steel and hardened. 212 MODERN MACHINE SHOP TOOLS. In Fig. 306 is shown a form of clamp dog very well adapted to the holding of tapered work. In Fig. 307 is shown a bolt dog. This tool is clamped to the face-plate so as to receive the head of the bolt. It will drive PIG. 306. square or hexagon head bolts, and, where a number are to be operated upon, will save the time that would be required to put on and take off the common dog. When a dog must be used on the threaded end of a bolt or i FIG. 307. spindle it is necessary to protect the thread, or it will -be injured by the dog screw. If the work to be drivegi does not require the screw to be tightened very hard, a heavy piece of brass over the thread will usually be found satisfactory. A common practice CHUCKS AND DRIVERS FOR LATHE WORK, 213 in cases of this kind is to jamb two nuts on the thread and place the dog on the outer nut. In Fig. 308 is shown a very satisfac- tory form of dog for use in such cases. It should be made of forged steel, tapped the required thread, and split as shown. The clamp screw locks it securely on the thread. A hexagon nut tapped and split through on one side may be locked on threaded work by clamping under the screw of the common lathe dog, thus making a safe driver for threaded work. FIG. 30S. PIG. 309. \''ery light work is frequently driven from the center without the use of a dog, thus enabling the work to be machined all over without changing ends. When an exact center is not required in the finished work the square center may he used to drive it. Instead of making a round center bearing on the live center end of the work, a pyramidal or square center is formed with a punch. r J— '-•-v ■ J. ; I I 1 ^ 'fU PIG. 310. FIG. 311. This bearing fits over a square live center, which drives the work. A square center is a difficult one to keep in proper shape. Another method of driving light work from the center consists in milling a thumb-nail notch in the live center end of the work, as shown at A in Fig. 309 and using a live center with a driver. as shown in Fig. 310. In this case true round centers are used. M4 MoiiERN MACHINE SHOP TOOLS. A erreat deal of work done between centers does not require 2 :!o^. as a face-plate stud or driver will engag-e some part of the kvork as shown, for example, in the case of a puUev in Fig. 311, The driver in such cases should be placed as far from the center as |)Ossible. thus making: it firmer and steadier. The face- plate driver should l)e a stiff, substantial one. A lK>lt strung full of nuts and washers will answer after a fashion, but the on? shown at A of steel, or at W of cast iron, in Fig. 312. will lie found much more satisfactor>-. Two or three lengths will usual- ly meet all requirements. lathes are usually provided with two face-plates, one of larp:e diameter and one of small. The small plate is the one usually used for driving the clog on work held between centers. It is generally a round plate with one or four notches. The plate shown in Fir^. 31^^ is sometimes used, but ^ , ^J{ II B ® [Of PK>i 312. WO. 313. for reasons of safety is not as good as the round one. At least one notch in each plate should extend well down to the center^ thus enabling the use of the smaller dogs when operating on lif^lit work. Lathe work not held between centers can be classified under the head of center- rest, carriage, face-plate and chuck work, the distinction l)etween the two last classes l)eing narrow. Center- rest work includes all in which the center-rest carries one end «.f the work and the live s])indle the other. Carriage work in- cludes such classes as are o])erated upon by a rotating cutter while secured to the carriage of the lathe. Chuck and face-plate work covers that wide range of operations upon work rigidly secure^l on the live spindle. The lathe chuck is a device for holding work more firmly and adjusting it more accurately than is conveniently possible when damped or ^^^c face-plate. Chucks are classified as in- CHUCKS AND DRIVERS FOU LATHE WORK. ^^5 dependent, universal and combination. In Fig. 314 is shown an independent four-jawed lathe chuck, The^^t- chucks are made with two, three or four jaws fitted accurately in radial ways in a substantial plate or body. Each jaw is uperated independently by a square-thread screw. The jaws may. in order liest to con* form to the character of the work, be reversed. The two-jawed chucks of this class are usually employed on special work; the FIG, 315, jaws being so formed as to receive special formed faces for hold- ing work of plain or irregular outline. The universal chuck, an example of which is shown in i-lg. 315, is usually a three-jawed chuck, althongh they may be had 21C MODERK MACHINE SHOP TOOLS. with two or four jaws. In this style of chuck the jaws all moij together. The mechanism of the three and four-jawed tinivt chucks usually consists of a geared scroll as sho>vTi in front and back views, Fifjs, 316 and 317. In the tw^o-jawcd universal the FIG, 3l6< FIG. 317. jaws arc connected by a right and left screw. The universal chuck is used mostly on milling ancl grinding machine heads* screw machines, cutting-off machines and other places where It IS dcsireil to quickly center round work. When new. first *cl 1 FIG. 318, FIG. 319, universal chucks center work very accurately : but after they comr somewhat worn they should not lie relied upon for e^ Jering, lie combination chuck involves both the universal and in<] CHLXKS AND DHlV£|iS TOR LATHK WORK. 217 pendent characteristics, as by a slight adjustment it may quickly be changed from one to the other* In many places a chuck ui this character is very well adapted, but for general, every -day lathe work the independetn four-jawed chuck is more suitable A combination chuck is shown front and sectional views in Figs Ji8 and 319. A combination scroll chuck is shown in section at X, Fig C B FIG, 320, FTO. ^21 f^ MODERX MACHCKE SHOP TOOLS. ^^2ii, with an end view of the jaw A an I> in its back. Fhe carriers C engage the scroll move Ingeiher. Hie screws B move ihc jaw^s A mdtpaidentlj A universal two- jawed chuck for holding firtnly bar work shown in Fig. 321. This is known as an auxiliary- screw chi The details of the jaws are shown in Fig. 322* Tbey arc ofia4 PIG. 3i2. ateil by the right and left screw\ which engages half nuts on tli side of the jaws. The auxiliary screw passes throuj^h ijnc the jaws on the oppfjsitc side from the main screw and ihreiid initt the nther jaw. -After closing the jaws onto the work with the double screvw tightening the auxiliary screw, which has a fine pitch thread, not only evens up. but increases the pre&smt of the jaws upon the work. In Fig. 323 is shown a face-plate jaw* These jaws, CHUCKS AND DRIVERS FOR LATHE WORK. rc self-contained, may be attached to a face-plate, and as such l^nstitute a tirst-class independent chuck. They make a very Itjstaciury substitute for the larger sizes of chucks, and are retiuejitly applied to very large face-plates. For special work, as the finishing of cocks, valves and fillings, PIG, 324, . revolving chuck of the character shown in Fig. 324 is used. Special jaws hold the work, and a suitahle indexing arrangetnent provides for exact division and rotation about an axis at right angles to the work spindle. CHAPTER XVII. LATHE WORK — BETWEEN CENTERS. One of the first and simplest jobs the beginner does in the lathe is to turn a plain spindle. He can begin, even on this job, to exercise his judgment. For example, he is given a bar of round steel 2 inches in diameter and is to make a plain, straight and true spindle ijs inches in diameter by 2 feet long. In cut- ting this bar he must make the necessary allowance for squaring up the ends. If cut in a cutting-oflF machine, 1-32 inch will do; if in the power hack saw 1-16 inch should answer if the saw is running reasonably true, while yi inch or even >i would usually be required if haggled off in the blacksmith shop. Having cut the bar and made the required allowance in length, he next centers it with punch and hammer. The proper locating and forming of centers in work to be machined between centers is of importance. When considerable stock is to be removed from the work, and it is therefore not necessary to use great care in locating the center, the careftil workman can, if the diameter of the work is not great, usually spot the center sufficiently near by eye. When the ends of the work are cut reasonably square, tlie bell center punch can be advantageously used as shown in Fig. 325. The punch should be held squarely over the work as shown at A. If the work is not sawed reasonably square this tool should n(.)t be used, as it will not show a true center as illustrated at r>. In P'ig. 7,2C) is shown a form of bell centering tool In which a conical recess in the base holds the lower end of the work true, while the bell which moves over a vertical guide lo- cates the upper center. This tool is very nicely adapted to the centering of a large variety of small work. The caliper-dividers (herma])hro(lite calipers) are perhaps more used for this work than any other tool. The legs are adjusted, as shown in Fig. 327, to a|)|)roxiinatcly the radius of the work, which has previous- ly been chalked on the end to more readily show the mark*;. Three or four arcs are then scribed from about equi-distant points on the circumference which intersect, as shown at A and B. The LATHE WORK — BETWEEN CENTERS. center of the small triangle in A and square in B are the approxi- mate centers. ^M For work of large diameter the center- head square as showw^ in Fig. 328 is nicely adapted. A line is scribed along the straight edge a b; the head is then carried about one-fourth around the work and another line c d scribed : the intersection of these line gives the center. By placing the work upon a plane surface the center can read- ily be found by means of the surface gauge, as shown in Fig. 33 'S 222 MODERN MACHINE SHOP TOOLS. Place the pointer at approximately the height of the center and scribe four lines, the work being rotated about 90 degrees for each line. The center of the small inclosed rectangle will be the approximate center of the work. A pair of dividers can be used in place of the surface gauge if desired. Having located and prick-punched the centers, they should next be drilled and reamed. If there is a small amount of stock requiring close centering, the work should be placed between centers and rotated on the light center-punch marks to determine whether they are sufficiently accurate. This is determined by giving the work fast rotation by drawing the hand over it quickly and holding a piece of chalk against it to show the high spots. If too badly out, the punch mark can be drawn over the re- quired amount before drilling the center. The form of center bearing should be as shown at B, Fig. 330. A hole of from 1-32 1 / ) < ; .r:d :::;] / A FIG. 330. c to 34 inch in diameter, depending on the diameter of the work, is first drilled and then countered with the 6o-degree counter reamer shown at A and B in Fig. 171. The hole must be drilled deep enough to prevent the lathe center from reaching the bottom. At C in Fig. 171 is shown a most excellent combination drill and center reamer for this purpose. The drill steadies the reamer and insures a true bearing and drilled hole of proper depth. The drilled hole not only protects the delicate point of the center, but serves as an oil reservoir to aid in lubricating the center bearing. It should be filled with oil before putting the work on the center. In large center bearings on very heavy work it is frequently desirable to cut with a small cape chisel one or more narrow grooves through the bearing portion to facilitate the oiling of the center. Where a large amount of centeriii?; vs. doT\c, *». w\^^\\tvr. iot LATHE VV(»HK — -ItKTW EEX CENTERS. 223 U work is tVequeinly employed, h is provided with a self- centering chuck for the work, which obviates the necessity of previously center^marking it. He now squares olT the ends with a side cutting tcKjl, and how isily he gels them square to the very center by slacking back Islightly on the tail spindle and allowing the tool to cut into the ■center. He must be particular about getting the bar to exact [length in this operation » and when finally to length the ends mui-i [look as shown at B in Fig. 330. To leave an end as shown at iC is unpardonable, even on the rougliest kind of work. When [left as shown at B a reliable center can l>e had at any time shtndd Mt ever become necessary to place t!ie spindle between center^ again. , He should next rough to within about 1-32 inch of the finished fc diameter for a length of from three to four inches from the tail ^■center, in doing this the center bearing at that end becomes ^pwom down to a nice, true bearing. The work is now changed end for end and the balance first roughed down and tlien finished. I It should be here noted that no part of the work should receive its final finishing cut until it has all been roughed over. The reasons for this are. first, that the centers should be worn down to true bearings, and second, because of the springing due to removing the fiber strains in the metal. If a part be given the final finish before the balance is roughed down, that part will I usually he found out of true after the last roughing. Not only IS this the case with the rolled metals» but with the cast as well, where the removal of the skin or scale usually causes the work to change somewhat in form. The required quality and truth of the finished surface must determine the numl>er of cuts to lake. For the roughest work ^H a single cut will frequently do, and for general work two cuts, ^rthe first a roughing leaving only enough for a finishing cut. The latter cut should always be a light one. When a very nice, trne surface is desired three cuts are advisable; a roughing, a sizing^ [and a finishing cut. In turning the above bar the young mechanic should learn a [lesson in cutting speeds. Mild steel can he machined at from 120 to 100 feet cutting s])ccd per minute, depending on its hard- fness and the quality of the cutting tool. The beginner usually runs way Ixdow speed, and as he hp« itio experience upon which to base his judgment in speeding 224 MODERN MACHINE SHOP TOOLS. work, lie should make a simple calculation in each case until his eye tells him the proper speed without figuring it. As the circumference of the work is approximately three times the diameter, he would in the present case have the work mov- ing to the tool about six inches per revolution. At a cutting speed of say 25 feet per minute, the work should make about fifty revolutions per minute. Chalking a spot on the face-plate and counting the revolutions will determine quickly whether or not the speed is correct. This matter of speed is of very great importance, not only in its eflPects upon the output of the lathe, but upon the workman himself, as he quickly becomes tuned with his machine and loses that snap and vigor at his work which comes from seeing even- thing move along at a quick, business-like pace. The young mechanic should familiarize himself at the begin- ning with all the details of construction and manipulation of the lathe itself. He will necessarily do work slowly at first, but he must learn accuracy from the beginning. The speed will come as he improves in skill and gains in confidence. He must learn early the power of the machine, the strengt'.i and wearing qualities of the cutting tools and the strength of the materials upon which he operates. He will then not overtax the machine and break or injure the tools and work; neither will he take three cuts over a piece of work when two would have an- swered quite as well. If the surface is to be a polished one, he must make some al- lowance for filing and finishing with emery. This is a matter of judgment, and the beginner's judgment is usually poor, as !ie leaves altogether too much to remove with the file, which takes up time and injures the truth of the work. It is very difficult to file much on rotating work and keep it cylindrically true. The finishing cut should therefore leave the surface smooth, true and within one to five thousandths of an inch of finished size, de- . pending on the degree of accuracy required. When the spindle is very long and its diameter relatively small, it becomes necessary to support it at sonic intermediate point or to provide some form of support immediately back of the cutting tool, as otherwise jt would, owing to its own weight and the pressure against the cut, spring excessively, causing it to chatter and leave an untrue surface. In such a case, the cut would have to be ver}' light to prevent \\\^ wotV ^xo\w V^^tv^wv^ r LATHE WORK — BETWBEK CE or climhin^ up on the point of the tool, which is a very exasperat- ing accident that frequently happens even when the greatest care is exercised, and it usually results in spoiling the work. The center or steady rest in its general form is shown at A in ^^^' 3i^* I*s construction is plainly seen from the fig^ure. The foot is clamped to the shears of the lathe at any convenient i>omt» and the three sliding jaws are so secured that ihey can he ad- justed upon a portion of the work's length that has previously been turned true and smooth. If the har is to be turned over its entire length, this spot is usually taken just off the middle point r and a little closer to the live center than the dead one. This en- ables the operator to turn from the dead center toward and some- w^hat past the middle* The work can then be reversed, the jaws adjusted to the turned portion and the balance of the >pindle machined. Truin^t: the spot is usually slow, as light cuts must be taken in order to i^et a round section that is concentric with the axis of rotation. It is also difficult to properly set the jaws of the center rest upon the spot without throwing the work center out of the line between the centers of the lathe. It is usually best to adjust the two bottom )a\NS ?vt«*X ^ivA. \Vvvv=k 226 MODERN MACHINE SHOP TOOLS. relieve the work of the deflection due to its own weight. The jaws, if set too tight upon the work, will heat and score it. Oil should always be used and the ends of the jaws kept in gooil condition. If the work is to be machined only at points on its length, then the center rest should be set as near as possible to the point where the work is being done, and thus give the greatest amount of rigidity. Frequently it becomes necessary to steady a bar for tuminjj that is not and cannot be made round at the point where thi center rest is to be applied. In such cases the device shown in Fig. 332, and commonly known as a cat head, may be used. It is FTG. 332. simply a collar turned round on its outer surface and provided with suitable set screws for centering it upon the work. This gives a round bearing which, as before, is made to run within the jaws of the center rest. The cat head must be so adjusted that it runs perfectly true on the outside or otherwise the work will not run true when the head is removed after turning. The effect of crowding the work, with one of the jaws out of its true axis of rotation, is to turn the work tapering. Thus, if the work is crowded by the center rest toward the tool, it will be turned smaller in the center than at the ends and in like manner larger at the center if crowded away from the tool. WTtical motion does not affect the diameter to so great an extent, since, if the tool is set at the height of the center, the work can be raised or depressed quite a distance without making much change in the LATHE WORK — BETWEEN CENTERS. 22J diameter. If. however, the tool sets above or below the center, a material taper will be given to the work. For example, if the tool sets above the center and the work is depressed at tho center rest, it will be turned larger in diameter at the rest than at the dead center. \'er}- often it is desirable to suppon the work right at the tool for the entire length of the cut. This is ac- complished by using the follow rest, an example of which :- shown at B in Fig. 531. It is quite similar in its mos: general form to the center rest, having two jaws, one behind and the other on top of the work. It is secured direct to the carnage an^i consequently moves with the tool. If the work is in the roug-i. the rest follows after the tool, but ii it has been pre\-icusly :n:t J. the rest may be set ahead of the tool. It is. however, usually preferable to have the rest follow rather :han lead the cutting- tool. For work of small diameter a single ;aw with a \*-t:r.-: serves well. The producii^ of satisfactor\- results in the use of the f-r'.Irw rest requires good judgment on the part cf the cperat.r. It should be set as soon as possible after the cut has '.eft the ieai center and while the work is rigid ano true. .\r.y :rrc;r-*ant:c^ in the work surface over which the ::*.'. :-.v rest r^sfc^ s^r.c to reproduce these same irregulahrles trr:-j:^:hout the Irn^.h :f the work, and it is, therefore, ver. in:r-:r:ir.t t: ^t^rt rxan/. right. In the cutting of rhreais :r. \:^^ li^ht r.-if the f:'.' . rest is indispensable. It is als-: :t \-a*ue :r. jtrai^-ir-c -^ r'-; :h -.: is being operated upco by a ctitrlr^-:n t>:'.. It :- ^iZKr. z : the center rest for this pcrr^rse. ruL^rr.urh as it -nr *•: r't'. - much closer to the pcint where th-e r-t :f ''k.tjz tikrr. An exanqdc of cccter rest -s^irk :* i:'?.-.-:. :". ru^ jjj H-rr. as is frequently the case, i: •>? nr'-iir-fi : i^rr^tt :r. :hr --.r. : : the work which precl-'ies the ttsO !:t: : rir^.ir.:: t'-i: :r. '. - the center. The center resc rarr:-rs th- z'-.r rr 1 :- ■ -i < .- \< moved back oat of the -xiy ir : th-: ::irT:i^t > j ■ - 1— - rocm tc gret th« to*:! ar the -^:rV fjrri.T T"--: -• — >- - firmly sectire*! to the hea.-: ^y.''.'- "'-■:-. 1 it-'-t "' i—j :. he had in thai ecc ■:: th^ * :r« -: > ♦:•- - :i — - - - ■ center. This rectiires 5.:r:e r:'z''.--*[ :' - - 1 — ■.'- - • - -. plate to prevent it fric: irx-= —^ ~ -'--: -'*:- - - - ha- a c-:nven:eEt iCi.Ji.-irr -.-tiir ''r-. :'-' - . -^ ---- --. ^ - the -a-AS .:f the zs:n- r-ist -ii r -\ - • .- \j.-- - sh- -Iter an-i thzs trr'trt :>.-: - -• -> — .-■ - - i - 228 MODERN MACHINE SHOP TCX)LS. the live center. A collar can be clamped on the work to accomp- lish this result, but this method is not satisfactory except, per- haps, in the case of very light work, as the center rest is not rigid against a side pressure and the cramp of the dog or driver is quite certain to crowd the work off the center. A clamp, as shown in Fig. 334, slipped over the work behind the dog and drawn, by means of bolts, firmly against the face-plate will l>e found quite satisfactory. It is necessary that the clamp be drawn up squarely, as otherwise the truth of the work, especially if light, will be affected. Tn cases where there is no center bearing in the live center end of the work, and one cannot conveniently be arranged for, that end can be carried in a chuck. If the chuck is an inde- ^1 iio. 334. ])en(lent one, the work must he very carefully centered in it. If a universal chuck is used and exact centering of the work is re- ((uired, it is equally necessary to test the truth of the work, as universal chucks, after being somewhat worn, lose their accuracy ior exact centering. The work should be caught close to the ends of the jaws, except in cases where the jaws and surface of the work gripped are known to be absolutely true ; otherwise the outer end of the work will be thrown out of the center of rota- tion and, if brought back by the center rest, a spring in the length of the work must result. U is. in any case, difficult to set the center rest so that it will hold ihe axis of the work exactly coin- cident with the line of the centers. If not so licld, tlie w'ork will run true, but all cuts will be tapering. If it is much out in this adjustment, it will cause the live cetUer end of the piece being machined to work on the centers or in the chuck jaws, the usual LATHE WORK — KETW EEN CENTERS. 229 result being the loss of the grip. The stiffer the work, the more noticeable this action. The turning of external tapers can be accomplished in several different ways. As above indicated, in center rest work, if the rest holds the end of the work so that its center is back or ahead of the line of centers, tapered work results. In like manner, where the work is carried on both centers, if the dead center is moved across the bed, the center line of the work will be at an angle with the direction of motion of the carriage#and tool, and tapered work results. As all engine lathes are provided with a set-r)ver adjustment in the tail-stock, this method of turning tapers is always available. As the amount of side adjustment is limited to a small range, only slight tapers can be produced in this man- ner, and especially so in cases where the work is long. Thus, if the tail center can be set over one inch and the work is four feet long, then, as shown in Fig. 335, it will be turned two inches Fio. 335. smaller at the dead center end than at the live center end, which would give a taper of one-half inch per foot. If the work was one foot long, as shown by the dotted lines, it would have a taper of two inches per foot. The above indicates the method for determining the amount to set the tail center over to produce any taper per foot within the limits of the adjustment. Thus, if the work is eighteen, inches long and a taper of five-eighths of an inch per foot is required, at one foot the offset would be one- half the required taper or five-sixteenths of an inch, and at one and one-half feet it would be iJ^iXS-i^^^ or 15.32 of an inch. This is, of course, only an approximate method for determin- ing the proper amount of set-over, as the exact amount must, Itv nearly every case, be found h\ trial. It \v\\\, \'vo\veveT, sct\^ Vv- 230 MODERN MAtHlNE SHOP TtltlLS. ter than a ^ess for the first trial. Tlie principal objection this method of taper turning is that the centers of the lathe no longer point toward each other, and the center bearings in the, work do not, therefore, bear properly uix)n them. This fr quently causes excessive wear on the hearings and sometime throws the work otit of true. The ends of the work must faced off perfectly square, or otherwise the work will be sur to run somewhat out when held on offset centers. Since in thi^ class, of turning the work does not stand at right angles to tfi face-plate, it is necessary' to low for some in-and-out moticn for the arm of the dog or drive through the face plate. Whc the lathe is provided with tajKi| attachment, as shown in Fig. ^^fi external tapers may be lurnc without offsetting the dead cenJ ter. This leaves the true beari ings on the centers and does ivH necessitate the difficulty of hav- ing to adjust the dead center U*r parallel turning each time after a taper job has been done, Ta|ier attachments are given a much wider range than can be obtained by offsetting the center and arr etpially as useful in boring tai>- ered holes as in turning external tapers. In all taper attachments the mechanism is such as to operate the tool rest direct from a guide set at any required angle, within its limits, with the shears of the lathe and independent of the cross-feed screw, yet at the same time retaining the in-and-out adjustment of the cross-feed screw. As several parts and con- sequent joints are required in such combinations, a considerable amnimt of back lash usually exists. The effect of this back lash is to let the tool start on a parallel cut until the back lash is taken up» when it starts off on the required taj>er. This can usually be overcome by carr>'ing the tool enough beyond the end of the work to allow the slack to take up by the time the tool is brought up to the cut. It will be understood thnt it is not necessary to let the feed bring l\^e loo\ v\v ^^ ' -^'^ '^'^ '^'^^'^ LATHE WORK — BETWEEN CENTERS. 23 1 be advanced quickly by hand, the only point being to carry it far enough to take up the slack by the time the tool reaches the work. On work of small diameter, where the tool strikes the side of the center if moved beyond the end of the work, the back lash can generally be taken up by pulling out or pushing sharply in on the tool post, depending on the direction of taper the at- tachment is set to turn. Thus, if it is set to turn an increasing taper from the dead center toward the live, the angle of the guide will be such that its end nearest the head stock will be the closest to the shears and the inside face of the block will be forc- ing the tool back from the center of rotation. It would then he necessary, in taking up the back lash at the beginning of the cut, to push the tool toward the center. The maximum range usual- ly given the taper attachment is four inches per foot. It is seldom necessary to turn or bore steeper tapers than can l)e bored with the taper attachment. When, however, such are required, a lathe with a compound rest can be used. Examples of the compound rest are shown in Figs. 242 and 243. Its con- struction is such as to allow the upper slide which carries the tool to be set and secured at any angular position with the cross slide, thus enabling the turning or boring of any taper. Although the range is small, steep tapers are usually short, and it is conse- quently seldom that the tool must be reset in turning any ordi- nary taper. When a lathe is to be kept continually on taper work, a po-^i- tive taper^tuming lathe is superior to one having a taper attach- ment. In lathes of this character the head and tail stocks are mounted upon an auxiliary bed or platen which is pivoted at tlu* center and clamped at each end of the main bed. The axial alignment of the head and tail spindles is maintained, thus allow- ing the work to bear squarely upon the centers. A suitable graduation at one end of the bed enables the operator to set the line of centers at any desired angle, within the range of the ma- chine, with the shears and line of travel of the tool. This ar- rangement not only possesses all tiie good features of the taper- turning attachment, but eliminates the troubles arising from back lash. In all taper turning it is necessary to set the point of ti.e cutting tool at the height of the center in order to obtain the taper indicated by any setting. If the tool is set above or M center, the resulting taper will be less : ''nrhtly concav* ^\^-' .M(.IiKKN MACIIINK SHOP TtK)I-S. In tiirninc: an external taper to fit a tapered bore the correct ta|Rr nui.si he obtained before the work is brought down to exaa >ize. In making the j)rebniinary setting for the first cut too ^rrcat rather than loo small a taper should result, as the measure- ment will be taktn at the small end, and if the taper is too small the work, while large enough at the small end, will l>e under size at the large end. In getting the exact taper the work should W tried in the bore after each cut. As long as the difference in taper is considerable the sense of feeling may l)e depended upon to determine which way to vary the taper in order that it may correspond with the taper of the bore. When too close to note the error by that means, draw three lines with chalk lengthwi^^ on the surface and at approximately equal distances apart. Place tlu- work in the bore and tuni it carefully through a complete rtvolmion. L'pon removing it, if the chalk marks have been *-H_ Li - I'Ki. 337. rubbed apparently equal their entire length, the taper is correct. if, Imwcver, the marks have rubbed at one end and not at the ntlur. a further al advance for each cut is usually gauged hy tneans of a graduated dial on the lathe cross-feed screw, or a threaded stop screws which can be turned back slightl> for each cut, thus allowing the tL»ol lo be set in a corresponding amount. When thoroughly practised in thread-cutting work the of>cr- ator usually gauges the amount of each cut instinctively by tlie osition of the cross-feed screw crank. iJHi LATHE WORK — BETWEEN CENTERS. 235 After each cut over the work, it is necessary to draw the tool out from the cut before reversing the work for returning the tool to the point of starting. This is due to the back lash in the long train connecting the tool and spindle. The tool should be carried slightly beyond the point of starting in order that the back lash will be taken up by the time it enters the cut. If it become necessary for any reason to remove the tool from the tool post before the thread is completed, great care must be ex- ercised in resetting it. The lathe should be run forward one or two, revolutions, which takes up the back lash and starts the carriage forward, after which the tool can be set to the groove already cut. After the thread is started, the driver should not be removed, and if the work is removed for testing, it is necessary to put it back on centers with the dog or driver engaging the same notch in the face-plate. For this reason it is preferable to use for threading a small single-notch face-plate. If the work is long and springy, the follow rest B, Fig. 331, should be used to support it. In cutting double threads it becomes necessary after the first thread has been completed to advance the cutting tool an amount equal to one half the pitch, as shown in Fig. 339. This may FIG. 339. FIG. 340. readily be accomplished as follows: In lathes where the ratio between stud and spindle is one, mark a tooth on the stud gear and the corresponding tooth-space on the intermediate gear. Drop the intermediate gear out of mesh and turn the spindle until one-half of the number of the teeth in the stud gear have passed the marked space on the intermediate gear. Throw the gears into mesh and proceed with the cutting. It is, of course, nece-> sary that the stud gear have an even number of teeth in the alxive case. If the ratio between stud and spindle '\s o\\\ct \\\^tv o.w»i. 236 MODERN MACHINE SHOP. TOOLS. the Stud gear must be rotated an amount proportional to tliat ratio. The better and more convenient metliod, however, is to have milled notches in the face-plate accurately indexed. Re- move the woi!' aid place the tail of the dog or driver in the notch diametrical!; opposite the one in which it was while the first thread N.as being, cut. For triple and quadruple threads the above methods are equa'H' applicable. As the common thread-cutting tool cannot be given any top rake it is not free cutting. The strain upon it is consequently great, and it at once becomes a hard tool to keep sharp and in proper condition. When the lathe has a compound rest the tool shown in Fig. 340 may be used for cutting V threads. The com- pound rest is set at Tx) degrees with the axis of the work as shown in Fig. 341, and the tool set with the thread gauge in the usual FIG. 341. manner. The tool is given top rake and cuts a clean chip from the end a, it being advanced to the work by the compound slide. Vov cutting square threads, the tool used resembles a cutting- off tool with the plane of the blade set at the angle of the pitch i)f the thread, as shown in the end view, Fig. 342. The amount of this angle varies for all jntches and diameters, but the side clearance is usually sufficient to allow some variation in diameters without changing the center angle. I-'or all classes of work on center it is very important that the centers be kept true and smooth. They are turned in the hcad- 'indle to the correct angle, tempered and ground. The tail or LATHE WORK — BETWEEN CENTERS. 237 dead center is ground first and the live center is then ground in place, and preferably not removed from its bearing after grind- ing. The live center should be marked close up to the nose of the spindle with a corresponding mark on the spindle, thus mak- ing it possible to always put it back in the same position. Before putting centers into their bearings, both surfaces should be carefully wiped clean and dry. In Fig. 343 is shown a form of lathe center that can be very easily kept in shape without excessive grinding. In most threading work on the lathe the nut is not opened from the lead screw after the thread is once started; the lathe after each cut being reversed and the tool run back to the be- 32 FIG. 342. Lm /'^^— GrouiMl FIG. 343. ginning of the thread. When the thread is a long one much time is lost by following this method, and the nut should be disengaged and the tool moved quickly back to the beginning of the thread. In all cases where the number of threads per inch being cut is a multiple of the number of threads per inch on the lead screw, they may be cut simply by engaging the nut at any position on the screw; thus, if the lead screw has six threads per inch, 6, 12, 18, 24, 30, etc., threads per inch may be cut by catching the thread at any point, it being impossible to catch the tool in any position other than the right one. The reason for this is evident from the following consideration. Assume the carriage and tool in the correct position and the nut engaged, the lead screw having say six threads per inch ; if now we open the nut and move the carriage in either direction, the nut cannot catch unvW \\\^ ca^t- 238 MODERN MACHINE SHOP TOOLS. riagc has moved a distance equal to the pitch of the lead screw or a sixth of an inch. For six threads this of course catches the next thread; for twelve threads it misses one and catches the second ; for eighteen it misses two and catches the third, etc. lu)r threads of which the number on the lead screw is a mul- tiple, as I, 2 and 3 with a six-pitch lead screw, the nut can readily be caught by inspection. Thus, if cutting one thread per inch the nut will catch exactly right on every sixth thread ; in cutting two threads it catches on every third thread, and in cutting three on every second thread. Inspection must determine whether it has caught the right thread before setting the tool into the cut. Other threads, as 8 or 10, may be caught by inspection ; thus on the six-thread lead screw, moving the nut three threads moves 1 — 1 [ 1 i ! 1 1 j FIG. 344. the point of the tool >< inch, which just catches the fourth thread on the eight-thread work, or the fifth thread on the ten-thread work. lM)r any pitch other than those for which the above is ap- plicable set the t(x)l for the cut slightly beyond the end of the work and mark the position of the carriage in any convenient way. A stop clanii)e(l to the bed against which the carriage may be brought is very convenient. Next mark the face-plate and note the position of this mark with reference to some fixed point on the lathe. After each cut open the nut, move the carriage to the stop and bring the face-plate to the mark, when the nut can be engaged with the lead screw, all parts being in the same posi- tion as when the thread was started. It is frcciucntly desirable to run a rough or cored hole on the dead center. This would quickly cut the center and ruin it ior accurate work until reground. The hole in work of that char- . VTHE WORK — BETWEEN CENTERS, 239 acter IS nsiiaily text large to run on the regular center, if such were clcsirable, and either a large center must be provided to carry it or the hole plugged and a center bearing put in the plug. If the hole is concentric with tlie surface to be machined the large center is the cheapest and most convenient method. It is, of rse, not adapted to tlie most accurate work, but for ordinary operation!* serves its purpose well. As it is necessary for the center to revolve with the work, to prevent its being cut, a special device is required. In Fig. 344 is shown such a center, common- ly known as a pipe center. The construction is evident : the cone revolves on a stud and backs against a collar havino; a simple bear- g surface to take the thrust. It is also provided with suitable channels for its proper lubrication. In Fig. 345 is shown an attachment secured to the carriage 1 ceni 1 ope cei de ly i re ftltii 1 i^- 345- an engine lathe for turning shafting. With this device the .haft is roughed down by two tools set opposite to each other, which serves to Imlance the pressure of the cut and reduce the IP ring to a minimum. After the roughing cuts, it passes through ^ suitable bushing held in the head and receives the final sizing and finishing cut from the tool shown at the back of the attach- lent. The device is simply a follow rest carrying three tools stead of one. I" ^igT' 346 is shown a device used on the lathe for the turn- g of cross*head pins or other surfaces the nature of which prc- nis the possibility of comjilete rotation of the work, fn thU MOUEKN &I VCliiNJC SHOV Trx>LS. 240 device a sleeve carrying two gear& is secured on the nose of th lathe spindle. The gear next lo ihe spindle bearing is keyeilj to the sleeve and rotates with the spin l independent of the spindle rotation. By properly pro|x>rtiotiinjj tlie diameter of the gears anrl the stroke of the rack, the v ' CAU he myde to oscillate back and forward through any <\^- part of the revolution, while the spindle has continuous forward Ftn. 346. rotation. Thus in the turning of the cross-head, pin shown, ll cross-head moves through rather more than one-half of the h revolution, thus enabling the turning of a little more than or half of the pin. The cross-head is then changed end for on the centers and the other half turned. Frequently, with cros heads to be used in single acting engines, where tlie pressure aji< wear arc always on one side of the pin, a large flat can lie chined on the non-bearing side of the pin and sufficient rotatic obtained to completely finish the pin without clianging cncj with the work, h is. of course, possible to turn a pin oi ih^ character without any special attachment, by either pulling xl belt backward and forward and driving the work in the ordiiiar LATHE WORK — BETWEEN CENTERS. 241 manner or by allowing it to rotate free of the centers and oscil- lating it by means of a wrench or lever. These latter methods are slow and require an extra workman. An ingenious lathe attachment for backing off the teeth of milling cutters is shown in Fig. 347. In a device of this character either the tool or the work must be given a slight in-and-out mo- tion for each tooth on the cutter being relieved. In the case shown, the tool is held in the tool post and advanced to its cut in the ordinary manner. The mandrel A of the attachment has its centers slightly eccentric, the amount of the eccentricity being FIG. 347. enough to produce the desired amount of relief on one tooth of the cutter if mounted directly on the mandrel. The arm L is secured to the mandrel and driven from the face-plate by the carrier D. The sleeve B, which carries the cutter being operated upon, revolves freely upon the mandrel. The gear b is secured 10 the sleeve and the gear a is loose on the sleeve, and is held from rotating by the arm d which is secured to it and rests upon the top of the tool ; c is a pinion carried loose on the stud D and gears with a and b. Gear b has a smaller number of teeth than a, and as a does not rotate, the rotation of the pinion c around a advances b and the sleeve and cutter a certain fixed amount at 242 MODERN MACHINE SHOP TOOLS. each revolution of the mandrel. The geared ratio is such fur any given number of teeth in the cutter that the advance per revolution is exactly ecjual to the circular pitch of the teeth in the cutter. The turning is such as to bring a tooth to the tool when the center of the mandrel is farthest from the tool, thus giving the relief as the tooth advances to the tool. It is evideiu from the above that the space between the teeth must be at least ecjual to the length of the tooth. As this division of space aii«I t(K)th in relieved milling cutters is not usual, it is necessary to allow the cutter blank to stand still while the mandrel is moving through a part of its revolution. This is accomplished by making the circular pitch of the teeth on al)out one-half the circumference of b e(|ual to that of the teeth on a and the teeth on the balance of b of somewhat greater circular pitch. For that portion where the teeth are the same on a and b, the pinion simply turns aruur.J both and the sleeve remains stationary. During the l)alance c.\ the' revolution, however, the sleeve will advance an amount equal to the circular jnlch of the cutter's tooth. With the regular tools and feeds on the engine lathe, i)larK\ cylindrical and conical surfaces are readily machined. If the sur- face is spherical or of irregular outline, a forming tool or sonic si)ecial attachment must be used on the lathe to produce the n- <|uired outline. If the work is of circular section, the forniin-; tool can usually be used to excellent advantage, as illustrated in iMg. 34S. In this case the tail-slock cap shown in the figure is first chucked, bored at A, faced at U anall in such cases not being cut from the body of the st tho tix>l bUx'k. On the outer end of the shank is secured a \nu^ lever or preferably a worm and gear mechanism for rotating ric. 35^^- Fio. 3Si' the cutter head and tool to the work. Although a truer sphere can l>c tduaiiH'd with this ilevicc than by the use of the fonninj; cutler shi)wii in F\^. 350. the surface will not be as smooth as with the latter. The mure elaborate device shown in Fig. 352 is better adaj^ted to the turning of larger balls than either of the methods alxne referred to. While this attachment can be pro- vi,r>g o^rati'jn under the first class was shown in Fig. ^^^. .\^ wjT'r: hanr< drill with holder, shown in Fig. 357. is fxrst suitcii to this work as it clears itself readily of the cuttings and the h..Mer prevents injury to the shank. In no case should the \2L\n:x >hank -inll tx: held by a dog secured on the shank, as it ir ijuite Certain to slip and injure the tool. If a dog is to be u^etl at all f'jr thi- piiq>'»se, it should l)e in connection with a straiirht eat ui)on. When considerable drilling «»i \\\\< kind i> i«j i)e d*^ne in a lathe, it is advisable to have a set of 'Irir: ^«ckct> fitted t«. the Ix-aring in the tail spindle. This not <»n!y inake^ a :r.«»re >atiNfact«)ry metho the danj^^er of the drill drawing off the tail center and beinj^ i>ent •►r ijp»ken by the cramp it would receive due to the sinj^lediandle*! Ivjlder. \\ hen h'des f»f a considerable depth are to be drilled in this manner in steel, it is difhcnlt to properly lubricate the cutting eil^^es (»f the arv to ta]) for a small gas pipe connection in the side LATHE WORK ON FACE-PLATE, ETC. 24y of the socket over the stipply hole in the shank of the drill. In an operation of this kind the important point is to get the drill started true. If the work has been centered for other operations previous to the drilling, this center forms a seat for steadying the point of the drill in starting. Even though this center runs perfectly true, it cannot be relied upon for starting the drill true. It is, therefore, necessary to steady the end of the drill in a dif- ferent manner. In Fig. 358 is shown a common method. The steadying tool, which is held in the tool post, is made to bear against the front side of the drill, as close to the point as pos- sible. The drill should be held so that one lip is on the back side of the work surface or opposite the steadying tool. As the cut is started, the drill is crowded slightly back of the center, making the one lip do all the cutting. This makes it virtually a rigid boring tool that cannot sway and produces a surface con- centric with the axis of rotation. Just before the drill begins to cut a full diameter hole, the steadN' tool should be backed away and the point of the drill left free to follow the center of rotation. If this work is carefully performed, it is possible to start a drill almost exactly true. When the surface into which the drill is to enter is plane, the centering tool with flat drill point shown in Fig. 359, and held in the tool post, is used. It forms a good seat for the drill to start in. For uniformly true and central holes the drill cannot be relied upon, and its use in the lathe is cortfined almost entirely to the opening up of the work previous to using a -boring tool. For example, if a i-inch hole is required in a piece of work held on a face plate or in a chuck, a i-inch drill could not be depended upon for anything like a satisfactory result and a 63-64-inch drill fol- lowed by a I-inch reamer would be almost as bad. The only correct way in such a case would be to firsl: use, say, a 15-16-inch drill which would remove most of the stock and allow a boring tool to enter. It can then be bored with the boring tool to the proper diameter or, if it is to be finished with a reamer, it should be bored to within about i-ioo of an inch of the exact size, which trues the hole perfectly previous to the reaming. The reamer should be held on the tail center, which latter must be exactly central. If the 1 *• '^flfset, a tapered hole will necessarily result. The » ig up previous to boring de- pcndtr '* the finished hole is to 2SO MODERN MACHIN'K SHOP TOOLS* be small in diameter and deep, a drill as large as possible should be used, since the boring tool will be a long and springy ore. In the boring of parallel holes, the height of the cutting erk rwiuires thought and judgtncat.] Fixed rules cannot be laid down, as each case must be considcml] from \u o^^ peculiarities. The surface to be machine*!, the ' character of die finish* the possible clianccs for gripping it in ihc chuck jaws, and the likelihood of the work's springing are all questions that arise with each case. Frequentl) the fi^nn of the work is such that it cannot Ik* held in tlic chuck. In such cases it is usually possible to clamp 4 PIG. 365. thr work to the face-plate or U) an angle-plaic secured on tl face-plalc Selling U]* work 111 this manner requires care an| time* If thcTc arc many similar pieces to he operated uiw^n. usually pays to get tii> a special chuck for holding them. Tak^ for exain(>te the cylitick-r head shown in Fig. 365^ Tliis head mu he bored oti the inside and facel bevels the end ; a roughing box tool ])asses over, taking the bulk of the stock; the finishing box tool reduces to exact diameter; the die LATHE WORK ON FACE-PLATE, ETC. 257 -tbreads it, and the cut of slide with an inverted tool in the back ]ioIc^ made to do a very wide range of work, but with turret ma- ofi-ines operating upon cast work, this is not usually the case, as «2i.<:h particular job usually requires its own special tools. Boring in the turret lathe is usually performed with a bar having a pilot XX^int and carrying suitable cutters, as shown in Fig. 369. A suitable bushing in the nose of the spindle steadies the pilot <^mtd of the bar. A roughing cutter is used to remove the heavy s>t:c)ck, and this is followed by a sizing cutter in a second bar, or if "tiVie distance from the inner end of the bore to the nose of the FIG. 369. spindle is sufficient, a sizing cutter may be used in the first bar. It should be so located that it does not start its cut until after the roughing cutter clears the work, as otherwise the spring of Ihe roughing cut will affect the truth of the finishing cut. It is usual to finish the hole to exact size with a reamer, carried also in the turret. The above is a job for a plain turret lathe. If face surfaces are to be machined, and the number of pieces required will war- rant making the tools, a facing cutter may be* used as shown in ^^S- 37^' The hole having been reamed to size in the work, the pilot bar P steadies the work while it is operated upon by the face cutter C, which is secured in a heavy cast head H, which in turn is bolted to one of the flat faces of the hexagon turret. Heavy spindle power is required to drive cuts of this character. 260 MODKRN MACHINE SHOP TOOLS. cud milling; cutter or a short l)orinf2: bar. The outer end of tht s[)iii(llc carries the j^ear I»: j^ear C meshes with L> and is carriei] ui? a radially adjustable stud, (icars IJ and C shouUl be maijc tn interchauj^e or even be rei)laced by others, and thus prondc tor chanji^es of s[)eed on the s])indle. The driving pulley E is carried l(X)se on a suitable stud D, which clamps over the nose of the tail s[)in(lle. A ])air of universal couplings with a telescf.-jv ing shaft connects E and C and transmits the power. In the operation of this attachment iK'lted power is transmitted to E and to the regular lathe feeds used for advancing the cutter to the work. The face plate must be blocked to prevent the work fiom turning. In iMg. 374 is shown a satisfactory meth(Kl of blocking the face ])late and, at the same time, of providinjj an adjustment for accurately locating the position of the l>oro. .\n attachment of this kind will fre(|uently be found quite valuable I'iG. :u3' Fict. .^74. a>. for example, in the boring of a crank disc for shaft am! crank pin. tiu- attachnunt boring the h(»le h>r the pin with ri-a sniiabK' certainly of getting it ])arallel with the bore for the crank ^iiaft. 1 ig. j^j^ serves to illuslratc a class of attachments that can Ik- advantageously u>e(l l"or performing milling operations on llio lathe, i'lie attachment shown is secured to the tool block in the place of the tool p<>>t. The construction is such as to ])rovi(U" i.)r siiitabU- \erlical adjustment, and the milling cutter to be usork. An attachment constructol along ihe same lines and attaches -slide can be made re by driving or by pressure. On small work the operator usually (lei)en(ls ui)on his judgment as to the [)ro[)er allowance. A differ- ence for each inch of diameter of the work of from .001 to .003 usually covers the range from medium to heavy forced fits. Shrink fits may be conveniently made on work of small or large diameter, as they involve only a means for healing up the ring or bore an amount sufficieiU to enlarge it, by expansion, enough to allow the shaft or center to enter easily. Driving fits are adaptable only to comparatively small diameters, as a hammer or sledge is usually empk)yed to drive the parts together, while the forced fits involve some form of powerful press. Forced fits also are adajnable to comparatively small diameters ; thus, the driving axle of a l(Komotive is forced into the hub of the driving wheel, but the tire of the wheel is always shrunk onto its center. Ill making forced fits the surfaces are coated witli oil, which is of course not done in shrink fits. In making a forced fit there is a tendency to swage the metal, •ile with the shrink fit the bore closes squarely down upon the LATHE WORK ON FACE-PLATE, ETC. 263 center. The atrains produced in either case are enormous. With a press fit it is very important that the parts come together squarely. With a shrink fit the bore usually expands enough to allow the shaft to enter freely. The correct placing of the parts together must be quickly done, as otherwise they will lock. Should the spindle fail to enter readily or stick before it is in the proper position, it must be instantly driven out. This may result from having allowed too much for the fit or from not heating the ring a sufficient amount. Forced fits being made with oil on the surfaces, which lubri- cates and preserves these surfaces, make it possible to remove by pressure the spindle when desired. With shrink fits this is not always possible, the surfaces are not lubricated and frequently the bore is heated an amount sufficient to cause a scale of oxide to fonii, which so roughens the surface that it clings firmly. If the bore is small the shaft can usually be moved by heating the ring and forcing under a powerful press. The shaft should be kept as cool as possible while the ring is being heated by appli- cation of cold water as close to the ring as possible. Care and judgment must be exercised, and even then the surfaces are quite certain to be injured by abrasion. When the work is of large diameter and the center can readily be kept cool as with the locomotive driving wheel the ring can be heated until it drops oflF from its own weight. From the above it will be noted that for work of large and medium diameter the shrink fit is most applicable and for w^ork of smaller diameter the forced fit is best. In fact on small diameters where there is any likelihood of ever wishing to separate the parts the shrink fit should not be used. CHAPTER XDC mmusG AMn TVitJdjiG mills. Boring and tttrnniig mttb ccMutitnie a special line of inadiine tool* marie neeeMar^ by modrm miftbiida of matin f act ure wbttt large mtmbcn of limitar parts arc to be handled aiv' in an economical manner. In Hg. jyj i» thown a 30-1 no. 377. am] turning mill of the vertical pattern. This represents the *vinallest mzc machine of this class regularly built. A cumparisun of this machine with an engine lathe reveals the fiaine characteristic elements in hoth* It is virtually a face plate lathe standing on end : the bed and upright corresponding to the head stock anle is a great point of advantage. In Fig. ^/H is shown a sectional view of the spindle and table bearing on the mill shown in Fig, 377. This large angular !)car- [ig has a self-centering tendency which tends to preserve align- FiG. 378. ment. This form of table bearing as well as the Bat and V bear- ings employed on other machines of this class provides a very lib- eral bearing surface; tlie ordinary weight load due to table and l^ork seldom exceeding 25 to 30 pounds per square incli of bear- ig surface. Where a dat licaring of large diameter is employed, jme builders provide a means of raising the table, for fast run- ling, from this bearing and running it in its spindle bearings, ising the end of the spindle for a step bearing. The small sized machines are usually provided with turret heads, either plain or ^ivel. Automatic feed in all directions with feed knock off is Usually provided. In Fig. 379 is shown a vertical boring mill of the larger class. The ttxil shown swings fourteen feet in diameter It is also made to swing twenty feet by using an extended base u^ou n4Vv\q?cv M€X)eftK MACHTXE SHOP TCX)LS, the houMngs arc «h:> moutucu mat inny may lie niovecl back frDn llic center of the table. In the exlctideii machines a radial arm ' inotuited upon tfie cross rail, carries a boring bar which is a»ed -3^355^ 1»1G. 379. for the hub work while the other heads are operating on the out-i side portions of the work. In V'\g. 380 is shown a standard horistontal lx)ring and drilling machine. The range of adaptability of tJiese tools is large, makJ ing them excellent tools fur general work, The work to be opcrJ BORING AND TfRNING MILLS. 267 jlted upon ts secured to tlie table which is adjustable in three dir<^- is, thus making it possible to bring any part of the work sur- ace into position to be operated upon by a toul lield in the boring ar. Graduated dials on all of the table operating screws make Kact spacings for holes in the work possible, a most valuable eature on many classes of work. For through w^ork, as in the :>ring of cylinders, the bar is sufficiently long to extend through lie outer support, a suitable cutter head being secured on the ir to carry the cutting tools. In the case of hores too small to How the main boring bar to pass through, smaller bars fitted to lie tapered bearing in the end of the main bar and fitting bush- ig:s in the outer support art used. The facing !iead shown at- Fio, 3S tached to the nose of the spindle may also be secured to the bar at any p<-^int, thus making it possible to face either end of work that the bar passes through. These machines may be advantage- ously used for heavy plain milling work. Another form of horizontal boring and drilling machine is vn in Fig. 381. Here the work table is mounted upon tlie ed and the vertical adjustment is obtained by moving the [}indle vertically over a substantia! upright. The outer bearing geared with the head, thus causing it to move with the spindle. Uitomatic table feed adds much to the conveni this tool or general work. BORING ANH TURNING MILL: :269 bine is shown in Fig. 382. The construction of the machine is "evident from the fig:ure. Atitomatic cross and vertical fectls are pnn'idetl for milling. In Fig. 383 is shown an example i>i a Hodr boring raill at work on a machine frame. In the floor horin^ and drillings machine of h'ig. 3S4 a uni- ?rsal lilting table is provided. When fitted with a revnlving We, operations can be performed on all sides and at a^ny angle a piece of work, t!ie bottom excepted, withowt changing its etting. Cylinders may be bored in the lathe in the vertical* horizontal PIG. Jlkl. or floor boring machines, but when a large araotint of tliat class of work is to be done, a special c>iindcr tioring machine* an tx- ample of which is showTi m Fig. 385, is generally employed. In this machine only those features of ibe horizontal mill nec4»«iry for the required work are reiainetl. A heavy l*oring fiar. rigid outer support, doable facing head and 00 vertical adjustment are the usual characteristics of these tools, T^^' usually id tn a suitable jig wfiich permits of rapid In securing work lo care and lie of the ver nill the When SfO UOOSMH SI ACBtKC SHOF TOOLS. possible the work is held in chttck jaws or in special drivcf«» i shown in Fig. 367. The latter inethocl has the advantage of not 1 tciuling to spring and affect the circnlar truth of the wori* aautj leaves, as in balance wheel turning, both edges of the rim tret 10 operate U[>ou. The turning and boring tools used in macfaioes o( ^1 .tv-^" l^i'f 51/ '1 FIG, 585. this clas^ are quite similar in those employed in engine lathe wortcj the grinding of the cutting edges being the same for similar work, The same bi:>ring bars, reamers and formed facing tools J used in turret lathes may be used in the vertical mill* For cylinder boring work in the horizontal nxiJU, the cullers areJ FIG. 386. usually carried in a *?pecial bead which fit?^ over the main boring bar and may be keyed and clamped at any position in its length* A head of this description is shown in Fig, 386. The cutting tools, ustially two or fquu||g|||g|^ are clamped in positioti and BORING AND TURNING MILLS. 271 should be supported as far out as possible. These too!* are preferably of self hardening steel ground to proper form fnnii the bar stock without forging. In Fig. 387 is shown the method of boring and facing a gas engine cylinder in the horizontal boring mill. The yoke jigs or frames holding the work are securely hoUed to the table arsd tlic work held by two set screws in each yoke. By means of these screws, and the table adjusting screws, the work can be trued W FIG. 387. concentrically with the bar. The head shown in F\^. 386 is passed through the bore on a moderately fine feed and removes the most I of the stock, the cut being divided between two or more cutters. HiL sizing cut is then taken back through the bore leaving only a ^■nall amount for the finishing cut. As the scale anLS. through on a coarse feed. This tool should have a broad cuttinj: c(lj;;c, very slij^fhlly rounded in its length; should l>e ground wiih very little clearance and stoned true and smooth. Its cut shoiiM he a light one ancl the cutting sj)eed well within the safe limit i-jr the steel employed. The object of the coarse feed is to fli>- tribute the cut over a greater length of tool edge and to perfurni the work with the fewest numl^er of revolutions possible, thus re- ducing the wear on the cutting edge to a minimum and pn^duc- ing a parallel l>ore. Where a numlxT of bores are to Ix; finishd to approximately the same diameter, it is advisable to have the fin- ishing to(jl set in an indei)endent head which can be substituted for the regular head. This virtually corres|x>nds to a reamer and makes possible very close duplication of bores. The end of the cylinder is next faced with the facing head shown, and if desired the holes for the cylinder head studs may be drilled and tapped by operating the cross and vertical tabic ai firesstire to come dtrectly in the line of the table'i» motior^ Suit- Fir.. 5^. liev-el gearing and tigln and loose pullei s on the outer tm of the sliafl ^ ' the driving mechanism. Tliis ih- *tetl^ for its smoLi i action, and trcLiuH> from the vi irc-f quently found in spur gear drive- Tlie mechanism for o[)erattng Uic iced is cumparaiivcly siiiij |rfe on most planers, the same mechanism usuall) vt^jeratit^ bothj vertical and cross feeds on the cross rail head, or heads wtie I'irc than t»ne are use ilk' tttii-ilt of die stroke i*arie%j it b necessary tliat the h ^tve the full amouutl )f i nt nf the taWe'i 1^ PLANING AND SHAPING MACHINES. V7 inake, should give the full feed adjustment for each stroke. In rig. 388 the arrangement shown is simple and effective and in snodified forms is largely used by the different builders. The head which operates the feed is drwen by the extended Rack FIG. 391. pillion shaft, the arrangement of parts being as shown in Fig. 392. The disc A is secured to the shaft and consequently ro- tates with the pinion, right or left handed rotation depending upon the direction in which the table is moving. The disc car- ries a casing B and cover C, the cover being held to B with the If. 1 iX^ /£);/;., , * f\ 1 I \ — ^T ® 1 FIG. 392. (^ three studs D D D and against the friction washers E and F with a uniform pressure by the spiral springs under the nuts on the studs. If the casing is relieved, it and the cover C, together with the wrist pin G, rotate until the casing is again held. In the back of the casing is a slot H into which the stationary pin I extend -TS M<>I>KKN MACIIINK SHOP TfXlLS. 1 TIh* Iciipth of this slot i.s ilctermined by the amount of casiit;' ri»tation rcqiiirol. In action, the tabic* starts l»ecn moved up or down, depending u|x)n which side of the irnter the \nn l.i i>. As the table continties its stroke, the (lis: A >lips between the washers E and \*, and (i remains stationan. W hen the tabk- Marts on its return stri»ke. A rotates in the opp.i- >ite direction, carryinjj with it l* anil K\ until the pin strikes lie other enil oi the slot, the rack having received motion in the »»j)- |H» from the center and is indei)endent of the lenjjih «»f the table stroke. A pinion X I gears with the rack and thmu^jh a shaft carries the gear A. Fi;;. 3i>3. Clear U rotates free on the shaft, gears with C, and on its face carries the double pawl I). If the lower foot of this jkiwI. a< it stands in the cut. is thrown in, ii slips on the up stroke «»i* I hi' rack, hut drives the gear 1' in the ilirc*ction of the arnnv tm the down stroke. If the upivr font is thrown in it slips on the down stn»ke and carries gear I! ill I hi- upposii^- dirtvuon. iIk* diri'ciinn of feed being reverse* 1. li is t'viiU'iu tliat witli ilu- wrist pin i i, h'ig. y)2, on the same si'le of till' cintir. ilu' fird ovonrs at llu' hej^inning of the forward stn»kv' wlu-n tin- fi'i'«l i> in inu* direction, and reversal of the fee'l makes it occur at tlu' Ivj^imiinj^^ iii tlu' return stroke. The wear nil tlu' iVcd nu'chanism is Kast when the ivc(\ occurs at the be- liiiiiiini; of the return sirnke. as it is imt then necessary to move tile lonl while cultiui^. ( Mi the other hand, feeding on the return ^irnke makes tlu- wear im the lo..l in dragi;intr hack somewliai i:fe/iter. When the head^ are at»ache- ini^s. they are lmvcu a vertical icvA nn the Imusing in a manner similar to that already described. r>y remnving the gear (.' fmiii the cri.'s.s screw ami puttint^ it on the fei-d rod, the vertical fee operati'd in a matiner similar tn that fnr the Imri/nntal feed. \ Q .- \ \ 1 • B '<^ ^4: ip ; 1 nr. PLANING AND SHAPING MACHINES. The size of a planer is determined by the length of its table, fie distance between housings and the maximtini distance be- k^een table and Ixtttom of cross rail. The extension side planer so constructed that the housing on the side opposite the driv- jlg^ and feed mechanisms can hf extended out over the widened In this tool, the capacity is increased by spreading the hous- 279 .>94^ ings, an extra long cross rail, t»f course, ticing required. This class q£ planer is of value in shops where only a small per cent of the work done requires a wii".' wn in I''i<^. 3SX i^ ilu- (^ne known as v-' '•• \ I^vl a:v! -N •-. w .juitL' i^tMicrally u>f(l. It is >tr'.'T '''\ ' .■v'^■ ^:> t\ r:\\ \> --wkV. a-- tn make il very vtronj:^ an i PLANING AND SHAPING MACHINES. 281 -^ided for their lubrication. The bearing surfaces are usually grooved to retain and distribute the oil with suitable wipers pro- vided to carry the lubricant to these surfaces. In Fig. 395 is shown a common and very efficient method. An oil well or pocKet is cored in the bed near the center of the table's motion, and a pair of conical rollers carried in a suitable frame and held agstinst the surface by a spring carries the oil from the well to the surface to be lubricated. The principal difficulty with this arrsingement comes when the table is worked on short stroke for a considerable length of time, as in that case the portion over the rollers only is properly lubricated. On long strokes, however, the^ action is perfect. The planer table is always provided with a large number of lioles for stops and for bolting the work to the table, also with svii table T-sIots. These holes should be drilled and reamed and tli^ T-slots planed or milled in order that the bolt heads may move freely in them. Fig. 396 shows a side view of a planer head. This same gen- -eral form is used by all builders on both the planer and shaper. It is nothing more than the compound rest on the lathe, having in -addition the tool box and apron. The cross rail corresponds to tlie carriage on the lathe. It is a rigid girder that contains the oross-fced screw and the vertical feed rod, and upon which the saddle travels, it being securely gibbed to the cross rail. The swing frame pivots at the center of the saddle's face and may be clamped at any desired angle, either side from the vertical, the amount of the angle being determined by graduations either on the edge of the frame or face of the saddle. The slider is gibbed to the swing frame and operated by the feed screw shown in the figure, either automatically or by hand. The automatic feed is accomplished in the same manner as for the compound rest, a section of which is illustrated in Fig. 243. The mechanism, of course, varies somewhat with the different builders. The tool box is pivoted to the slider and has a limited amount of adjust- ment each side from the center, being clamped rigidly in any de- sired position by the lock bolts shown. The apron, which fits neatly in the tool box, is pivoted to the box at the upper forward corner, thus allowing it to swing outward on the return stroke and prevent the tool from dragging heavily over the work surface. The tool post is secured to the apron. The office of the tool box is to allow the tool to swing out from the work on the return '^^2 J'XJ^,€' ii:SK nFfOP T«'^*T>. "< .-.^ ^'STistce^. I" i.-i eviiient that if iht ir. ior jr. ptvoterl airrctlv to the slider, 'i'.i'ht -vjc ''jti the return stroke, which ' 'tf'r' '-'.'rr. rr^.'.r.inine z^/p -ur faces. If. however. • '-r-- '-kr.:r.'r': :he r ''1*^/1. in swing^inj.^ straij^ht o'ji. ;, ■' v-r •'•■ ' irihr.f, plane^I. injurin;^ the t'Xil anl \rv<**- V. h'Ti however, the apron pivot.^ to a tof^l */" ir»'!irjf'i Vimewhat away from the wnrk sur- i;i" . If J- #v;'!fijf ♦hat th'- i*^.:nt of the XfirA will, iifxjn the return \VtVt', -wm;.' 'HIT ivAVi thf work : hut if the top of the tool Ixjx \r. \ut \\ui'f\ Mt\\:xrt\ til* -i'W- of the work, the tool will swing; into the wnxV -iirf;i'«-. *aM-ifit: tronhU-. It is therefore necessary to swing thr Ik.x in tin: opi^isit^- 'lireciion when changing from one side of ■•/.- '-".rVA-'-- v.o:I'l *\x'A't!! M\:\XT\\\\' •}.' l**./ »h;it ' ;iT 0! J. idJ .V :o fFl^^ ._ ■UJ - L :■.-- 1-ir.. ,v)7. 'I" \\«mK i.» I 111' oilinv riu' tl |iusi .Is iisiMJ ,.n ilu- latlu'. luit it is more commonly a p. Ml .'I » l.mi|is. .Is shcnvn in hij^. ^V)7. W Imi p. kni'wn .is ilu si.uMlart! >liapor is of the column or pil- 1 \\ pit I, Ml. «Mh ilrsti^n oi wliioli is sh(»wn in \*\^. y^j^. with sevenl iMp, 1 iii.h hmrtus yu^ W A\:^\x\WA latorK In this machine ilu ■.M". i-h; ••, i.ii'uJ ilu- v'v'hitun. Tlu* cross rail is j^hbeil in '•* ■•'"■. u* I'StI ^'* ,^im'«i.i!>!r Nv-nivMliy In a suitable elevating • • ' ^^ ■ ■!* I*''\ t^: kmv\' Is s^\ri'.iii ii> a ^aiMlo which moves 'Ai. ■'•• «•»'•■ • ;■■ riu- \,v\\ \\\\'w^ \\\y' :.'.'■ lu-a*l wliich is \\\ iv-"-} ^^ -^ " ••• ■•* •'•^' ^*'-v" »\ s,T''\i! a-^ vv". :!'.i- h«nMi. tlu* >\viii.i: ■■■'•' ■ ■ •• ■ I-.' **^ "vM-*< . ' :-. u»'v,'. ;;c.:.r .1:'..' !\iv.,! wheel, wliiob . ■•■'■. ■ ■ ■■"•^ ' ■ u''\- ■■■. ■•*.iv-:'"\- -v :' A. : !.'.'>!. V.I.' ' .« C ' " ' * v' ■"■'%'.•. ^ v" '»"!"■.;*';'* PLANING AND SHAPING MACHINES. In all shapers the ram is actuated by one of two methods, le geared method provides for a rack and gear drive similar to that lused in operating tlie tahlt? in the planer. It is simpW a geared reduction, the quick return to the ram being accomplished "by either the use of a smaller backin^^ pulley or higher belt vein- 4aty for the return stroke. Hiis drive is illustrated in Fig, 389. ■ In Fig. 399 is shown a standard pattern shaper having a rack and gear drive. This drive, although little used on small ma- rlines, is always a]>plied on the larger shapers. Machines of pattern shown in Fig. 399 are regularly made in sizes from -inch stroke np to 48'inch stroke. The other method is known as the crank drive, in which a crank or its equivalent, operated by a suital>le system of gearSr transmits the motion to the ram. The use of the simple crank drive has been superseded by crank drives which involve a quick- return motion. With the simple crank motion, not only is tRe time occupied on the return stroke of the ram equal to that on the forw^ard stroke, but the relative velocity of the ram varies ^freatly between the begintiing and the end of the stroke, being ^uch more rapid at the middle than at the ends. With the quick- return motion, however, it is intended to reduce the time during which the ram is on ils return stroke and thus give more time for VODERK UACUIKE 5B0F tUOtS. the forift-ard or cutting slrukc, and abo to average tip as mu possible the relative vdodty of the rani at the fliffer tkm of Its forward stroke. In all cases the power i<» c caled to a shaft, usually by a 1>elt running on a stepped causing it to rotate at a uniform rate of speed. Crank shapers as regularly made run in sizes from 14-inchj to 30-tnch stroke. In Fig. 400 is shown the mechanism commonly known as ih slotted or vibrating link. P is a pinion recei\4ng motion tr FIG. 399, ihe licked cone at a iinrlonn rale of roiatiun, and gearing witi the gear G. The link M M (nvots at the point L and carries at its upper curt the rocl R wliieii connects with the ram at H. /lH block B is fitted nicfly in a slot S in the link and is carried olB the pin T which projects from the face of the gear G< The path of the pin is a a, the block M moving np and down in the s1q|H and causing the link to vilirate about L througrh the limits y ^^H carrying with it the rod R and rhc ram. If G rotates in the fLANlKc; AND SHAPING MACHINES. tion shown by the arrow and the tool end of the ram is at K, the forward part of the stroke occupies that portion of G's ition indicated by the angle x and the rctnrn portion by the jlc y. It is, therefore, evident that the return stroke occupies i?iG. 399B- less than one*half of the revolution of G* An analysis of f mechanism shows the mulion of the ram to be much move iform than with the simple crank, the velocity being faster the beginning and end of the stroke and slower through 286 MODERN MACHINE SHOP TOOLS. middle portions. As more of the time of each revoltition is cupied by the cutting stroke with the quick return than with simple crank motion, the velocity of the cut will be lower more uniform, thus enabling a greater number of strokes minute to be taken than would be permissible with the sir crank motion. By carrying the pin I toward its center of r tion, the length of the stroke may be shortened by any des amount. The Whitworth quick return motion, as illustrated in Fig. fk;. 400. is very larpjely used for shapcr drives. Referring to the fi r is the i)inited to the machining <)f widely separated surfaces on heavy Jes of work. iu the classes of shapers above illustrated the cutting stroke lie outward or, push stroke. In the Morton or draw stroke ^^r shown in Fig. 404 the reverse is the case, as tlie tool cuts le inward or draw^ stroke. This tool has been very success- 290 MfFDKRX MAi IHNK Mi or looL^. fully used on heavy work and lon^ stroke.^, and has l:>ecT» ^i!wt mudificd by its liuilders to suit special conditions. The he; alone, attached to a suitable knee plate and driven by flex shaft, rope transmission or electricity, is quite extensively sl- a portable shaper 10 be clamped to the work that is to be chined. Many of the cutting tools used on the planer and shaper j — L J i'Uy. 404- the same as those used on the lathe, as, for example » the cutting, diamond point and cutting-off tools. There are. ever, several forms specially adapted to planing operations, extended nose tool shown in Fig. 405 is used for cutting ways or for any class of internal work. This tool, unless SB and heav}% springs badly. It should be held as high in the hoUler as permissible, thus reilucing the spring to the least amc possible. The shape of the cutting edge is suited to the chara of the work and should be given as small an 1^ mount of \yoii PLAN I KG AND SHAl'lNG MACHINES. 291 earance as will enable it to take hold of the cut. otherwise it ill dig into the work hadl>. The Armstrong plaru-r tool shown Fig. 406 takes the place of several forms of ordinary planer >Is. as top roughing^, right and left side roughing and right and feft under-cut, all as shown in the figure. It may also be used to (lold cutting-oflf blades or formed cutters of any class. A tool ^f this kind for the planer possesses the many advantages of Sdr FIG. 405. fy^n FIG. 406, Fir,. 407, re ■ ba Bus similar tools for the lathe in which a small cutting tool of self- liardening steel, ground rather than forged to shape, is used. The gang tool shown in Fig. 407 is often used on the planer where the surface to be machined is large and comparatively regular in outline. It consists, as shown, of several tools set one back of another in a suitable head held in the tool clamps in the ■usual manner. The cutting points are so adjusted that each kes the regular cut desired so that a regular feed of. say, 1-16 inch on each cutter would, on a gang cutter tool, enable the head 2y_' MODICKN MACIIIXE SHOP T«X)LS. 1 to I)f t\'«I nvor the surface one-fourth of an inch at each >troke »■»!' the work. A tool of this class carrying a roug^hing and i nn- ishinj^ cutter must not be depended upon to pn.idiice satisfaa«'r work when good machined surfaces are required, as the j»iirinu of the roughing cutter due to the ine have the cutting edge well back iinrler the head so that the spring of the tool and head will not cau^t n n I <^ l-IC. 40S. K ^] U I'n.. 4(K>. tl.t rniiint; edge to dip into the work surface: it also tends t. ]»n*vciii chattering. This p«»iiit i^ illu>iraied in Fig. 408, whca ai \ i> >lio\vn a t'^-l whose vuiting e*lge i> well ahead, and at U Mil.- with llu* cutting rdm- well back. The doited line> show ill. jiath llu- riUlini; edge tend> to i\>llnw in each case, due to tin- -|»ring «»f llu' i«M)l itself. The >pring of the head tend> in rarli ca-r t«t let llu- p.'int int.* the work, but uk»\ ><> l»adly in the i-A^v -li«'wn at I*. a> ai A. ( )n all top and side cuts the tcol -wiiiL:- "nt and away fr'»m the wirk surface- on the return stroke. l-.^r !ni'l« r r\u^, li..\\c'Ver, except those ^^i c<»mparaiively slight anL'l< iT'/ni llu- \trtical, wlure the head can be angled l»'» meet tl.r «'.ii.liti..n. ili« !•"•] n:;i>t ''e luM fr- -ii^ -winging "Ut «»ti the r >h- -wn in i'iir. 4-^t As the t^ol PLANING AND SHAPING MACHINES. 293 <^ags back heavily in such cases, the wear on it is excessive. -A side head, due to its position, is well adapted to under-cut ^ork. Where much under-cut work is to be done and a side liead is not available, or owing to the position of the work sur- face, not adapted, a relieving tool similar to the one shown in Fig. 410 can be made at a small expense. In this tool a stud projecting from the side of the shank carries a small tool hold- ing collar, which can rotate on the stud until the stop A strikes the shank. A light spring S bears against the stop, al- lowing it and the tool to swing back from the work on the re- turn stroke and bringing it back again for the beginning of the forward stroke. For finishing cuts at coarse feeds the broad nose tool shown in Fig. 411 is u^ed. The corners are slightly - -e 1 m /±yy FIG. 410. FIG. 411. rounded, as shown at A, B, and the tool given only a slight amount of clearance, as shown. The planer and shaper, when equipped with suitable attach- ments, are capable of a very wide range of what might be termed special tooling operations. An emery-grinding head is secured to the cross rail with suitable belted connections to drive its wheel and the planer table at the proper speeds, and the planer is ccn- verted into a very creditable plane grinding machine. This transformation, however, is not to be advocated, as the bearing surfaces of the planer are not properly designed for the pro- tection necessary against the flying particles of emery. The cj"- version, however, into a plane milling machine is more com- mendable, as the planer when provided with suitable feeds for the table is fairly well adapted to milling work. In Fig. 412 is illustrated a device that can readily be attached to the cross riil of any planer, virtually converting it into a slab milling machnv;. The head of this attachment is so construjled that the spindle 2t>4 MOUBKK MACinKB SIIOI' TfJOLS, can be swivelctl from horizontal to verttcal. \s there art nmnv operations that can he more advantageously performed hv milling ' than by planing, an attachment of this kind will frequently be | of value in cases where a slab milling machine is not available. In Fig. 413 is shown an attachment for planing concave or con- vex surfaces. It consists principally of a vise pivoted in stiita- ble housings at the ixnnis O O. The arm S is a pan of the vixi | jrCv- PIC. 412. carries within it a stud it^rminating in the guulc K The liar G G is secured at any desired angle with the table to the jjusi P» which is fastened to the side of the planer bed. If G G is parallel to the work table the vise will have no motion relative to its housing. If the bar is set as show^n in the figure the farther end of the vise elevates as the table advances to the cut and at concave stirface results. By inclining the bar in the np^MJStte direction* however, the end drops as the table advances to the cm and a convex surface rt^sults. The arc of the circle plant^l depends on the amount of the angle between fl e clamped on it, a rotatintj feed motion. This device can also be mo. 416. secured to the knee in a horizon- tal position for operatinj^ upon special work requiring the ma- chining of radial surfaces. The circular attachment shown in the center of the foreground is provided with an arbor carrving two cones. Work having any bore within the limits of the cones can be held on the at- tachment, an automatic feed giving the work feed rotation. The index centers shown on the right are in principle similar to those shown 10 Fig. 416. They are, however, self-contained, both head and tail stock being secured on a suitable base casting, which in turn may be secured to the knee of the shaper. In Fig. 399 A is shown the circular attachment as used on the **Ctncinnati" shapers. The spindle is driven by a worm and gear, either by hand, or automatically by the power feed inechanism shown. In Fig. 399 B is shown the automatic head feed used on this shaper It is a positive acting mechanism, having a variable feed ailjuslment, Tlie action corresponds to that used on the planer ad feed, the short side shaft corresponding to the feed shaft in J^j^ MfXlERS MACHINE SHOP TfKlLS. flir rrriss rail and the motion is transmitted to the nut by two \i'A,T'^ ijf miicr jjtars. Spiral planing attachments similar to the one shown in Fij;. 3^^ are frerjuently applied to planers for the gfrooving of spinl ri>ns and work of that class. Another attachment for the cuttii.;j iA s|)irals on the planer consists of a rack secured to the side of the f>Ianer lied at alx)ut the height of the surface of the work tafile. A |)inion carried on a shaft running in bearings secured to the surface of the table and at right angles to its length gears with the rack. This cross shaft through a pair of bevel gears transmits -its motion to a spindle parallel with the table's length and tri which the work to l>e spirally planed is attached. The nioti(»ii of the table causes the shaft, spindle and work to rotate at a rate determined by the velwity ratio of the gears. A sliaper is sometimes used for key seating bores. There is a vertical supporting knee attached to the table for holding the work, and a s|)ecial head attached to the ram in place of the ordinary tool box. This head holds a cutter l>ar, which is in the form of a broach, and will cut the key way at one stroke of tlie ram. CHAPTER XXI. PLANER AND SHAPER WORK. The proper securing of work in the vise or on the shaper or planer table for planing operations is a most important step in the production of satisfactory work. As the variety of work as- signed to these machines is great, the operator continually finds himself against a new problem requiring good judgment and care. In most cases much more skill is required in the setting up of the work than in the machining. When the work is com- pact and heavy, and the amount of metal to be removed is rela- tively small, the danger of springing it is not usually great. If, however, the work is large, of irregular shape or light, the danger of springing is great. The springing is due to two causes: First, by ununiform or severe clamping which distorts the work and throws the machined surfaces out when it is un- damped ; second, the removal of the outer surface of a castinjj or forging, which frequently relieves shrinkage and forging strains and throws the work out of true. The first of these troubles can be overcome only by using the utmost care in setting up the work, and the second by, so far as possible, first roughing ofT all surfaces before taking any finishing cuts, thus allowing the work, after the roughing, to assume its normal condition as to strains. The most important consideration in the clamping of work to the table is to locate the points of clamp pressure directly over the points of support. The supports should be firm and bear as equally as possible between the work and the table. When only a thin shim is required to level up the work, it should preferably be of metal, as cardboard, leather or any compressible material will allow the clamp to spring the work. Good blocks and parallel bars are indispensable in the planer outfit. For work where tnc points of support vary in height, leveling wedges and small jack screws are most excellent, as they can be quickly adjusted to any desired height. These leveling wedges, especially if a single wedge is used, should be made with only a slight taper. In F\^. 417 is shown a pair of these wedges. When carefully made they form a good support and may be used to make the fine adjust- MoUEkN \TuiJISi >iiOi' TimiLn. mem ioT heii^ht eithc'r uirctiiv on tlic vvurk labk* r^r on I' other hkicking. The planer jacks shown in Fig, 418 arc excellent* a few of these frequently replacing a large numi PIG. 417. Mocks of miscellaneous sha|>es imd sijces. A jfood set of plamr bolts shoulil be found on each macliine. Common machine b are noi well suited to this puqiosc as the heads arc too tlii PIC. 4t8. iuul not large enough to properly fill the T-slot. Planer liolts are preferably matle of mild steel with heads turned to rcqairal thickness ann the comers of the work. The clamp shown in Fig. o is made from square iron and forms a substantial and con- arm ient form of clamp. Clamps of this character should be ap- L^d to the work in the manner shown in Fig. 421, as closely as n D FIG. 4JO. possible; that is, the bolt should stand close to the edge of the work and the blocking for the outer end of the clamp as far away from the bolt as convenient, thus throwing most of the bolt pull upon the work and not upon the blocking, as would be the FIG. 421. FIG. 422. FIG. 423. :ase if the bolt was nearer the blocking than the work. The T-slots should be sufficiently deep to prevent any reasonable bolt Dull from breaking them out. This danger is, however, lessened 302 MODERN MACHINE SHOP TOOLS. by placing the work or its point of support as close up to die bolt as possible. If the entire surface of the work is to be rhachined, clamps as above described cannot conveniently be used as it would necessitate changing their position during the cut, a most deli- cate operation with results usually unsatisfactory if a true surface is required. When the work has considerable thickness, small lugs or flanges can be cast on the edges for holding the clamp point and in some cases a drilled hole in the edge of the work can be made to receive the point of the clamp. In cases where these methods are not convenient, the work can be held in the manner shown in Fig. 422. Two forms of post are shown in this figure, the one a plain pin to fit neatly in the round holes in the table and the other with rectangular base and tongue to fit ]'!(;. 424. the T-slots. A common set screw with cone ])oint fits any of the tapped holes in the post, the height of these holes varying to suit the thickness of the work and length of finger used. The fingers are cupped to receive the point of the screw and the work end pointed to engage a prick-]3unch hole in the side of the w^ork or preferably formed fiat as shown in the figure. A suitable post to receive the end thrust of the tool nnist in all cases be set ahead of the work, and should be made of steel, preferably a low grade of tool steel, to insure stiffness, and turned to fit neatly the holes in the table. It should extend well into the hole, but should not reach high above the table, from two to four inches being ample. The shorter it is. the less liable it is to get bent. In Fig. 423 is shown such a post. The two holes drilled through it at right angles to each other facilitate turning or prying it ii]). when, from any cause, it may stick too tight in the hole to l)e pulled out with the fingers. PLANER AND SHAPER WORK. 303 Round work may be held as shown in Figs. 424 and 425. In Fig. 424 the bar rests on the edges of the T-slot. In this case the edges should be in good condition. It is suitable for bars of small diameter only, while with the method shown in Fig. 425 where a knee plate is used a bar of any diameter can easily be held. A pair of V-blocks can be used very advantageously for hold- FiG. 425. ing round work. These blocks as shown in Fig. 426, should be tongued to fit the wards in the table and the V-notches planed with the blocks in place. A good knee plate is frequently quite necessary m the securing 1 ; ■ i I I I I I I — \' r I I FIG. 426. of work on the planer table. The regular knee on the shaper, however, serves the purpose on that tool. On long work the twisting, and deflection due to the weight of the work itself, must, where accuracy is required, be taken carefully 304 MODERN MACHINE SHOP TOOLS. into consideration. For example, long lathe and planer beds must in the machining be handled with great care. Take a lathe bed that is to rest upon legs at each end. It should have the seats upon which the legs are bolted planed first, the points of sup- port being not at the extreme ends but at points about one-fourth the bed's length from each end, with wedges so adjusted as not to twist the bed in its length. After planing the leg seats the bed can be turned over and clamped directly on these seats, the bed assuming its natural deflection, in which position the shear?^ are planed. In securing work in the vise, the pressure of the jaw against iV.e work should be as uniform along the surface gripped as pos- sible. If the surface is somewhat irregular a soft packing, as paper or leather, will equalize the pressure. If there is mtidi irregularity, however, it is preferable to cause the vise jaws to grip the work at points rather than throughout their entire length. For this purpose a wedge or solid block should be used between the work and jaw and located as near the ends of the jaws as possil^le. When a jaw is tightened onto the work its tendency is to lift, causing the work to lift on the movable jaw- side. For this reason the movable jaw should be fitted nicely to its slide with bolts, as previously shown in Fig. 414, for clampinj; it firmly after gripping against the work. Planer vise jaws are usually made of cast iron, and a false facing of soft steel secured with bolts to these jaws is excellent when finished surfaces are to he gripped between them. It is important for nice work to keep the vise jaws in good condition. The leveling and sfjuaring uj) of work on the planer table is important. If the work has been laid oat or some of its surfaces previously machined, the surface gauge will be used in bringing these lines or surfaces jjarallcl with the table. If a line on the work is to be set parallel with the line of motion of the table, the surface gaui^^e needle point will be adjusted to the line at one end with the base of the gauge against the side of the slider. The table is then moved under the cross rail and the other end of the line brought to coincide with the point of the needle. Another method is to square tip from lines that have previously been l)laned with a fine sharp-pointed tool in the top surface of the table, and with the caliper divider caliper from the blade of the scjuare to each end of the line on the work ; or, if this line is not too far from the edge of the planer table, the cali])cring may be PL.\NER AND SHAPER WORK. 305 ii^tbt line to a straight edge placed against the side of the e table. When the line on the work surface is to be set at t angles to the length of the bed, the work is brought close o the cross rail and the line adjusted to the surface gauge Ic point, with the base of the gauge resting against the face le cross rail ; or, as in the other case, the caliper divider with raight edge placed against the face of the cross rail can be n the manipulation of the planer and shaper the beginner lid keep a few points closely in mind. All planers and geared «rs do not have a fixed length of stroke, the depth of the cut the speed of the countershaft affecting slightly the points at :h reversals take place. Some allowance must therefore be e for the overtravel of the tool. An excessive amount of over- el, however, means a large loss of time. Roughing cuts lid be as heavy and at as coarse feeds as the machine will leniently handle and the strength and character of the wo^k permit. Before planing side surfaces see that the top of the box is inclined from the work. This allows the tool to swing and clear the work surface on the return stroke. If it is not ned the point of the tool drags hard on the work surface, and lid it be inclined to the wrong side the tool will swing into work, doing much damage. Raising the tool clear of the k on the return stroke preserves the cutting edge. Means automatically accomplishing this are frequently employed, p the cross rail clamped firmly to the housings when in use parallel with the table. Before putting in the feed see that feed gear is on the right spindle, as otherwise the tool may : up or down when it is intended to move across the work, there are usually more ways than one to do every piece of k. study the way in which it can best be done. The manner ^hich the work is set up, the kind of tools used and the way 'hich they are ground, as well as the efficient handling of the hine, all have an important bearing on the quality and amount le work turned out. «#»< Re ♦37. m^ Tva Wtic At pinar ot tbr oM^ ^ H S&1IK A^ cm the shapcr. the ram mores m ^ rertkal , 9iiki|«ltti|s: it h> w<^k in nhicfa sortaces at n^hf ^urtav>- *-■ ^> he mudiioctL The t^fc whidi THE SLOTTIXC, MACHINE AND KEY SKATER. 307 .ibbed to the knee of the machine, thus providing a work at may uc rotated or moved to any position in its plane to the cutting tool and within the capacity limits of tlie e. t slotter is very largely used for the cutting of key ways »s and the machining of rectangular, circular or irregular *s which cannot readily he done on shaper, lathe or miH- achine. In Fig. 428 is shown a piece of work well adapted .' slotting machine. The surfaces a, b, and c can be ma- d on the slotter more advantageously than on the planer or FIG. 42S. laper, as the side rests solidly upon the table and the form of tlu- otting tool is adapted to the job. CJn planer or shaper a knee late must be used to clamp the work to, and an extension tool nployed- The half boxes used on locomotive driving axles as shown in ig. 429 illustrate another slotter job. Mere the cylindrical bear- 1^ surface is macluned by placing the work concentric with le work table. The tabic is so placed with reference to the tool lat the necessary amount of rotation can be obtained without iterfering with the tool or head. After each downward or cui- ng stroke the table is automatically rotated the necessary amount f feed for the next cut. By using a fine feed and a projxTly 3o8 MODERN MACHINE SHOi* TOOLS. formed cutting edge on the tool very smooth true surfaces rcsdt Connecting-rod ends and crank eyes are advantageously no- chined on the slotter. The tools for the slotter are either forged on the end of hean square bars of steel or inserted in steel bars of either square or round section. When forged the tool is usually of the foroi ^shown in Fig. 430. The cutting angles are the reverse of the*:* of lathe and planer tools. The end angle turns the chip and is the angle of rake with x as the angle of clearance. -\s wth planer tools the angle of clearance should he small in order w prevent the tool from chattering and digging into the work. The I'iG. 429, FIG. 450. angle of rake y should 1)C as great as the hardness of the metal c)])CTated upon will permit. For squaring out corners a tool similar to the diamond point is usually used. r)y properly indexing the rotating table spur an«l internal gear may be cut on the slotter. using a cutter of the cor- rect tooth s])ace outline. The key seater is an outgrowth from the slotting machine. and although designed for cutting key ways only, will, when ])rovi(led with suitable attachments, j)erform various classes o\ slotting machine work. A standard key seater is shown in Fi^. 431. A cutter bar is operated by a crank mention in the base oi the machine, similar to the drive on a slotting machine. Tiit THE SLoi ii\^; MAriiJNK AND KEV SKATKH. y^j end of the bar ts >upporter| by a suitable overhanging arm, work table upon which tlic pulley or ^ear to be key-waycfl aported inay be tilted the necessary amount to give llie re- d taper in the key way, and is also capable of a slight in and ption, independent of the k'til which advances it to the cul- his motion is necessary in order to clear the cntter from ^ing on the return stroke. form of cutter used on this machine is shown in Fig* 432 THE SLOTTING MACHINE AND KEY SEATER. 3II ?r to work out square comers. For the cutting of external ways in short shafts and spiders the key-seater is excellently >ted. ^or the key-seating of very large, heavy work portable key- iTs are used. In Fig. 434 is shown a Morton portable ma- e operating on a large pulley. These tools are made in four », ranging from 24 to 72 inch stroke. They are virtually V stroke shapers without columns. They are operated eitTier I rope transmission or electrically, a motor in the latter case g attached directly to the machine. CFIAPTER XXIII. MILLING MACHINES. riie milling machine and its great popularity are due to the ])cciiliar adaptability of the rotating cutter to the machining oi plane and irregular surfaces on such a wide variety of work. The variety of work that the milling machine is capable of per- forming is much greater than can ordinarily be accomplished on the planer or shaper. In thoroughly familiarizing himself with these machines the mechanic has much more to learn as to set- tings and manii)ulation in the milling machine than in the planer and shaper. With the latter machines, however, more skill is required in the manipulation for the production of accurate work than with the former. This arises from the fact that on the planer all measurements must be separately made, inasmuch as the cutting tool generates the profile of the work by a series of l)arailel cuts, all changes in plane of the profile requiring sepa- rate adjustments and measurements. With the milling machine, however, the cutter is so formed as to generate the full profile of the work surface as the cutter advances, setting measurements alone being necessary. With the i)laning machines the accuracy of the work depends very largely upon the personal skill of the operator, while with the milling machine the accuracy of the cutting l(X)l has nuich to do with the (piality of *the work. With the milling cutter and the work once set, the accuracy with which a certain work-surface profile can be produced upon one or more pieces de])en(ls wholly upon the wear on the cuttin^^ v(\\j^v<> of the cutter. As the cutters are usually formed with a number of teeth, the work is divided up among these teeth, rc- (iucin;^ the wear upon them. Tliis is not only because each unit of length of each tooth performs only a small portion of the total work as C(Mnpare(l with the cutting t^d^e of the planer tool of unit's leui^th, but because that particular portion of the tooth is ]>crforminix w(.rk for only a small portion of each revolution, thus giving it an o])porliuiity to cool and recover before each time it comes in ccnUact with the work. The advantage of the milling machine over the planer lies very largely in its ability to produce, with reasonable accuracy, a large MILLING MACHINES. 3 13 number of duplicate surfaces, the formed cutter and removal of the personal error in the making of measurements by the oper- ator being the factors that enable it to produce these results. For the producing of many plane surfaces, and especially on work that is not to be duplicated, the milling machine possesses no advantage over the planer and shaper. Its advantages for certain classes of work, however, are great, as illustrated, for example, in I'^ig. 435. This shows a milling gang cutter made up of seven cutters and capable of producing at one traverse over the work a ]>rofile that, if produced in a planer, would require no less than eleven separate measurements, aside from the working out to lino of the curved portion. It is only after the operator has become skilled in its use and thoroughly familiar with its every detail that he can appreciate the great capabilities of this class of ma- chine tO(3ls. When used as a manufacturing tool, producing large numbers FK'. 435. of duplicate parts, the results obtained from the use of the milling machine lies almost wholly in the intelligent selecting of proper cutters and fixtures for each special operation and when once set does not require highly skilled labor to operate it. When used as a jobbing machine, however, the operator should be quick and skillful to obtain gooK«>f MACHf?*K $Hor TOOLS. with uperatinf^ handles conveniently place*! and moving over dials RTaduaied to tncasure the aiiiuunt (if table movcmetii in thoiisandtlis of an inch. The knee is ^ibbeil to the face nf the column and, in the universal machine, the work table is gllM in a swinp frame which |>ivots to a *ihder which in turn is i^hhvi tu tlie upper face of the knee. Through the office nf the >vviTit frame the table can be set at an angle from its rifjht-anglt.' ]m\ lion with the cutter spindle- In some machines the tahic can he carried through a complete revolution, while with oihr^ the range is limited. The table is provntled wiih a loiigitudinil feed automatically operated in either direction. An automatic I'lci, 456. in-and-out and up-and-ilown feed may also he applied when sired. The feed mechanisms arc so designed as to give a wide range of feeds. The universal head, to he described hereafter, may t)e geared with the longitudinal fecattern are similar in design to the one shown in Fig. 437. In this ly^je of machine the work tahk- is gibhed directly tc* the slider and its line of travel restrained entirely to one at right angles to the spindle. The universal head and imlstock of the universal type- ire omitted, plain dividing centers usually being used on these MI U.I NO MACHINES. 31 I machines. The work lahle is somewhat larger on the plain than cm like sizes of the universal machine. The plain machines arc preferable for plain millings vvcirk, as they are snmewhal more rigid and simpler in construction. For tool room work the universal column pattern machine stands at the front. As prohahlv more than 95 per cent nf iht milling work outside of the tool room is plain milling, we find the plain machine much in favor for general work. Ahhough thej Ci)l«mn pattern is gtnerally conceded as the proper st\le of desigitl for the universal machines, such is not always the case fur plain FIG. 437- I machines, inasmuch as a great jjart nt the plain milling runs intu larger atul heavier work. We therefore find plain milling machines l)uilt along entirely ditferent lines, esjiecially when used f(^r the plainest and heavier classes uf work. In Mg, 458 is shown a form of plain machine commonly known as the Lincoln pattern. It is an exceerhngly simple form r«f machine, yet very efftcient on certain classes of work. The outhoard support, for tire spindle, tt»gether with die form of the bed. makes a rigid ma- chine. The driving cone is mounted on the badk side of the main iiO UUUU.RS MAtiiiNii sum- iUULS. riG. 4^9. MILLINC MACHTS'ES, 3«7 upright, driving the spindle through a pinion and gear connec- tion. As the vertical adjustment i'^ in the spindle itself instead of in the work table, a suitable tighlener is employed fur keeping the belt tensions correct for all positions of the spindle. The work table is given the usual automatic feed under the spindle an<1 suitable lateral hand ailjustmetii. In Fig. 439 is shown a form of plain milling machines somewhat similar in appearance to the one showm in Fig, 438. The design* however, provides for a 318 *N mm: II I chtJic. It re*iemblc!* in appearance a planer, is a niai^*iivc. p' ful machine, and in ihc form shown carries a large slal „ cttttcr for removing heavy cuts at coarse feeds from the work. These machines arc also provide*! wixh horizcmlat Si|>incile5 which can be operated with or indepemlcmh of the vertical spindlcv In thiii case the horizontal spindle iKrarings are carried on the front faces of the housings. Tlie vertical spindles usually carr} rmm] mills. The advamagi' cut the pressure is mostly III the direction of the line uf the feed and not at right angles to tlie surface hoing machined, thus overcoming most of the springing in the work that occurs or lends to ixcur in the use of the axial cotter. The radial cutter, however^ does not leave as nooth a surface as the axial hut this disadvantage is, on a great MILLlNt: MACHINES. 3»9 v ihc ^rreatcr accuracy obtained. In Fig. 441 is shown a well-known vertical milling machine intendcti for such general work as can be more advantageously performed by a cutter operated in a vertical spindle than by one on the horizontal spindle pactern machines. This machine in many respects resembles the regular column pattern machines with the column carried upward and out over the table an amount sufficient to bring the spindle into the vertical position, The vertical spindle brings the cutter more directly under the sight and control of the operator than when cutters of the radial class are used in the horizontal spindle machines. This type of machine also has the advantage of a circular feed by which a circular table, upon which work is placed, may be given a rotary motion. Thus a class of work may tie performed that would otherwise require the use of formed n tW lathe, and it can be done more quickly th^" »- Another form is for holding the clamping bolts and fixtures. The taljle is gibbed to the bed to prevent lifting and usually moves in flat or angular guides. The overlianging arm is usually made of the style shown in Mg. 436. which enables it to be used to receive and supf>nn the several s|>ecial attachments made to be used in connection with ma- chines of the column pattern. Suitable ties are now furnished with most makes of milling machines connecting the outer end of the overhanging arm with the knee, which adds much to the rigidity of the table and s|jincile when heavy cuts are being taken. A comparatively wide range of feeds to the table of the milling machine is consirlered quite important and esfjecially 3-22 MODKRN MACHINE SHOP TCK)I-S. 5t> on tlie l)ack-p^earo(l machines where the variation of the size and >|)ce(l of cutters is considerable. This range of feed is uM^ally accomplished by means of stepped pulleys, gearing, or a combination of the two. Thus a pair of four-step pulleys will ^'\\(i four chanj^^es of speed and if these pulleys are of different sizes, by transposing tliem on their spindles four more changes may be obtained. The power of the feed mechanism must be sufficient to pull tin- feeds under all conditions, and convenient in changing from one rate of ivvd to another. The importance of l)eing able to make (|uick changes may Ik illustrated in the case of large dia- meter end (^r radial milling cutters operating ujx^n wide work, rile rate of feed on entering and leaving the work can be ma- terially greater than when the cut is operating on the full width of tlu- work. If the cuts are comparatively short the time saved by entering and leaving the work on quicker feed is of material inip(»rtance. ( >n machines other than the smaller sizes, automatic in and out and vertical power feeds are usually provided. The all-gear feed mechanism used on the Cincinnati millinji machines is shown in detail in Figs. 445 A and R and 446 A anair of index centers. Suitable sigs on the botiom fit neatly in the neck of ihe T slots on Ihe P'ork table, thus preserving the alignment of head and tail spin- lies. The head spindle is capable of rotation only. It carries PIC. 445A- FIG. 445B. 324 MODKRX M Aril IKE SHor TCHiLS* a worm gear which \» operated by the worm ami cran The raiici between worm aiid gear is, on all indexi]| one to forty. In tlie one illui^trated there are So lcd| gear ancj a double thread on the worm. It is therefofl sary to make 40 turns of the crank and worn) to makti i .c. .» r-^. d. rrr, 446x1. o/ the gear ami spinvlle. The crank moves over a varx-txillv divided dial which is s^^ureil to the head. A snuiU piii. vul instable radially in the crank, may be set to en^^e in ihc lu^Ies smalU several plat OS are necessary in order to get the range of ili visions \iv iiall>' required. \\'ith the one shmvn thrtv plates are ttnishod. inal. with maiiy of the imeven divisions l>et\veen 50 and ux\ and n\an\ evon and uneven dixnsions alx^ve 100. The secti^r serves w ass^ist in counting the numl>er of s|>aces iK'tween the holes aiul ran 1>e adjusted to include any desired nimil>er of sj^ices luiwivn it 5^ two radial arms. As much of the miscellaneous dividing work di>no o\\ \\\\ FIG. 447. index head is for 2, 3. 4, 6, 8, 12 and 24 parts, a more rapid means of obtaining these divisions than by turning the won 11 is frequently applied. In the centers shown, there are J4 holes, equally spaced, in the face of the worm gear, with a substaulial pin arranged to engage in them. When dividing by thcM* linlc^ the worm is dropped out of mesh with the gear. The universal head is a more complicated piece of nuchan ism. In Fig. 448 are shown side and enrl sectional views of iIk- I»rown & Sharpe imiversal dividing head. A side view i>^ shown in Fig. 449. The worm gear \\ is attached to tin- spindle, and a side shaft carries the worm A. The spindle head is mounted in a suitable hou'^in^' and < an be elevated through an angle of f/> degree* and brnjl\ < lamp* d in any position. The spindle may also ]>*- depre^-e«l !hi/,M^di a few degrees. The universal head, as made by some builder- 1-. ca])able of spindle settings at any angle within o and \y^t *U"^rti>., When used for plain indexing the w^/rm «mi Jht divfigai^^d p6 MOUfiRX HAOIIJ^E SHOP Tf)r)r> from the spindle gear and the reqtrired divtjiion olitaind k means of the index |>latir C, which is hx^ketl in pfisiticm In tW pin D. As only a limited nunihrr nf JKUinns c;*n convemmlt "1 fiG u^ FIG, 449. be obtained in ihis way, the usual method '^ ^'v ?i>r; secured to the worm shaft, iind the *eci M I LLI NG M AC H 1 N KS. 327 held by a spring between the dividing plate and the crank \vitl\ just enough friction to keep it in position when set. The sleeve to which the index plate I is secured, carries a gear on its inner end which meshes with another gear on the axis R and about which the head rotates in setting to different angles. This latter gear meshes with a third gear on the same axis and secured to the upper of a pair of spiral gears, which transmit the motion from the train of gears leading from the table feed screw. A post may be drawn out from the head and caused to engage in a suitable notch in the back of the plate, or, in cases where the holes are drilled through the plate, in one of FIG. 451- FIG. 452. the holes. This secures the dividing plate from rotation and divi- sions on the spindle are obtained in the same manner as described above. When it is required to rotate the spindle while the work is being operated upon by the cutter, as is the case in the cutting of spirals, a geared combination between the worm spindle and the table feed mechanism becomes necessary. The milling machine is capable of receiving a large variety of attachments for performing special operations, or regular opera- tions with greater facility than can be had with the machine in its standard form. The vise is a regular attachment on all universal machines 328 MODHRX MACHINE SHOP TOOI-S. and plain machines of the column pattern. It is of two standard forms: plain, as shown in Fig. 450, and swivel as shown in lij:. 45 1 . The plain vise is provided with tongues to fit the wards in the work table and can \yc readily set with the jaws parallel with or at right angles to the spinclle. It cannot, however, be con- veniently set at any other angle. The swivel vise has a gradu- ated base resting on a plate which is tongued and bolted to the wards in the table. The swivel vise is very convenient for angu- lar milling. A special tilting vise shown in Fig. 452 is, with its tilting jaws and swivel base, well adapted to the milling of a large variety of angular surfaces. In all milling machine vises the movable jaw is accurately fitted and gibbed to the body, and the jaw faces, which are usually made of soft steel, are secured to the jaws by means of screws. The surface of the jaw facc> should be kept true and smooth, as they will then hold finished work surfaces true for the cut and without injury to the work. Extra jaw faces hardened and with roughed surfaces may Ik* used for holding forgings, castings and rough work. For the holding of special and irregular work special formed jaw faces may be substituted for the regular ones. As the universal dividing head is a part of the universal milling machine, it is not considered as an attachment. The plain index head already described under Fig. 447, however, is strictly a milling machine attachment. A first-class, three- jawed universal chuck fitted to the spindle of the index head is a very necessary accessory to the machine, as much of the work to l)c- operated upon can or must be held in the chuck. The vertical s])indle milling head shown in Fig. 453, when ap- ])lie(l to the plain or universal machines, converts them into verti- cal spindle machines. These heads are supported on the overhang- ing arm. and the nose of the spindle bearing. The vertical s|)in(lle is driven from the main spindle by bevel gears. A graduated index enables it to be set at any desired angle from the vertical, thus making it p(\ssible to mill many angular sur- faces with a ])lain end or shank milling cutter. These attach- ments are very convenient for the cutting of T-slots, key seating and profiling, as well as angular work. Another attachment. termed a universal milling attachment, is shown in Fig. 454. This has in addition to the vertical sinndle an auxiliary one at right angles to it and driven from it by means (^f spiral gears. With this auxiliary spindle set parallel with the surface of the UIU.1KG |lACHI3i£& FIG* 453* T~r'^ FIG. 454. MO SIUDEMX MACmxe SUOI* TIKILS. work tabic and its line of travel it makes a convenient rack ting atiachmeni* In connection with the spiral head on the i versal machines, it can be used to advantage in cutting spirals i large ^tpiral angle, as the axi?i of the cutter can W M!t to spiral angle instead of the work tabic. The auxiliary ^pind can readily Ix* removed when not in use, leaving a simple vcrtic milling attiichnu-nl. Attachments of this class l>ecome ai <\n value in shops when (he amount of work that can lie advama on*l> done by vertical milling does not warrant putting in a vc lal milling machine. In Fig. 455 is shown a circular milling attachment. It listji of a circular y»1ate gihbcd to a round liase and prnvtcM wcirm gear tnt*i which the feed wnnn meshe*;. The base cb to the table of the milling machine and the work is secured I n« iss- c top of the circular tabic, suital»le T-slots being provide the clanij) bolts. 1 his attachment lii of sjiecial value on the vc cal milling machines and in connection with the vertical milling^ attachments on the column pattern i>lain and universal machiii| It may be provided with an autuniaiic feed, w'hich incrc materially its usefulness wliere a considerable amount of w^ is to lie tlone on it. This aitachmenl can, when the table is ably gibbed to the base* be clanii>ed to a substantial right knee plate and the faces and periphery of work, as gear bU |julleys, etc, successfully milled with cutters on the main -piij of the machine. F(jr this class of work an attachment similii the one shown in Fig, 456 is l)est adapted. The rnnstnictifn this attachment is eviilcnl. As shown, it is art k blanks to be operated upon at the same time, tl MltXlNC; MAritfVES. m Tt is frequently desirable to use cutters of small dianieter and piring high rotative speed in tliu lart^^cT mzc^ of milling ma- As the spindle speeds are allogeiher loo slow for this FIG. 456- p, high ?f»rt 457' ^' ne of uhich is shown ' the front face ving the small I small \>inion .u^ MUDIlKN M.UIIINE SHOI* TCK>LS. which meshes with an internal gear srit^tJ ^n the nose of the main spindle. A rack-cutting attachment is shoun in 1 ig, 458. A ticvtcc similar to this is necessary when racks of any considerable length arc to be cut on a milling machine, as the motion of the table in line with the spindle is not great, and the distance the cutter can l)e set from the nose of the spindle is also smalK With the at- tachment shown, the length of the rack section that cam lie art at one setting is limited by the longitudinal travel of the table. hi the device shown, the frame is securely attached to the front face of the column, antl the cutter spindle rlriven by a suitable chain uf gears. The rack blank is clamped in the special vise sliuwn, and the depth and settings for t^ach cut are obtained by means of the graduated dials on elevating and longitudinal screws. The feed is in and out by hand, or automatically, if the machine is provided with automatic lateral feeds. The spiral cutting attachment shown in Fig* 459 is adapted* in connection with the plain milling machine, to the cutting of spirals. It frequently happens that the amount of spiral milling to be done in a sht>p would not warrant putting in a universal mnchinc, and in such cases the attachment sho\m serves its pur- pose admirably. It consists uf a circular base, carrying a suitable frame in wliicli a work talile is gibberL The frame is preferably detachable from the base, graduated antl capable of being clamped at any (lesired angle with the spindle nf the machine. The work table carries a head and tail stock for supporting the work. The TK he I M I LLI XC. M ACII I N ES. 335 head stock spindle carries at its outer end a bevel gear which revolves upon it. The rear face of the bevel gear is provided with circles of drilled holes, similar to an index plate. A radial arm keyed to the spindle carries a pin which engages in the holes of the plate and through which the drive is carried from the FIG. 459. gears to the spindle. The balance of the gear combination is a suitable system of change gears substantially as described in con- nection with the universal dividing head. A worm feed operated by hand is usually provided on attachments of this class. An attachment for the cutting of cams is shown in Fig; M-xL m^ttNa MACHINE FIG. 460. 460. It consists of a base plate A, which can be bolted to the work table of the milling machine, and a head stock which is mounted on the slide C. C is gibbed to slide in the base plate. The head stock carries a spindle with a worm gear G on its outer end. The worm S engages the gear and the spin- dle is given a slow feed rotation by the pulley P or a crank which 334 MoriRRN MAt HIXK siinr Tr»r n *r;i!i lie sijh.stt luted lii ii^i pl.uv wiicn j"p%\cfc i'-^m ■> not availabt.1 R 16 a iimall roller nitnintcd on a siii tabic !>uj>iHjri which extendi upwanl from the base plaitr. lite master cam F, which Jsoftltl .same contour as the requirecl cam. is moimted on the spindle, i>| is also the work. The w<»rk tahW of the milling machines 4 jusietl vertically and laicratly so as to hrinj^ the center of tlipj roller R and the millinff cittter in the same axial line. A wei \V connected by a rope, over a sheave at the entl of ihcUhl^l with the slide t\ holds the master cam constantly in c»:mtaci with I the roller as the spindle an ifjjper cnii, ami at tlk' lower end Is damped to a yoke casting which is secured N> tlic fruiit face uf tlic cukiinn. The guide may he set at any angle between o and lo degrees either side of the center h'ne. Motion is ^iven the slide hy a crank screwed on the nose nf the spindle. The stroke of the slide can he adjusted to any required length between o and 2 inches* The tools, which FIG. 46^ are provided with }4-inch ronnif shanks, are firmly clamped in position. In the use of the attachment Ijolh the longitudinal and transverse table feeds are available and by means of the gradu- ated dials very accurate readings can be made* This attachment is specially valunhle in tlie forming of special tools, jigs» dies and templates. CIIAPTKR XXIV. Ml LI. I NT, MAC II I M-: ( LTTKRS. Vhc milling of metallic surfaces requires a rotatinjc: cutter pr^- \i(le«l wiili <.!ie <»r iimre Itelli havinjj an eilfjc and temper suiipl to tlie nature of the material i>i)erate(l upon. As to construaii.n. millinj^^ cutters may he divided into iho two classes — solid aivl iu>crteil tiMJth. All >mall and most of the iiici nf ihe sleel i> an imiM)rtant iK»int, which, together with ilu' ri>k> iuci«leni tn the ])r«>per hardeninjj^ of such larjj^e masxs i'f i«Mil sttH-l. warrants the j^reaier expenditure of lalx^r usiialli ?ine<**ar\ in the making of inserted tooih cutters. The in>cnc«: t'H.ili culler lia> mily teeth of tool steel, the core i»r hody Inriiij: «'f cast irnu «tr uiiM sleel. \n 1.1 ila>^iticaii«»u. millini;: cutters naturally fall under fi-ur lu;ids. :i^ il'lerniiiu d h\ the four distinct varieties oi w«>rk jur- ii'mu'd. a*- h»llo\\>: Axial — those cutters use ^hi'w?) AW axial or plain millinjt;^ cutter, a*- il i- '^-iiali. ^allr.l. It ha- teeth • )n the c\ lindrical surface tmly. whicli. win II ilir I'uiter excrds aln 'Ut <»ue-half inch in thickne*^>. arv • :!i -|.iiall\. a> -liMwn in the t'lLiure. When the.se ciUter> are '» -- ihan ihr<'e sixiti-niliN . -t" an inch iti thickness, they are callcl :i;i 1 II ^liiiin^ -aw-, and the -i are j^muud slightly
  • hiii.L:. •.\!;i.li -rr\(^ 1.. L:i\.- iju' terth clearance in the j4:rooves they cut. 1 I'.i- i- ( r much ini]W'rtance whin the cut is the w<=rk ihr -nd«leu release of pressure MILLIKG MACHINE CUTTEKS 3S7 "causes reverse spring. If the cut is not deep, and only one or two leeth cutting at a time this effect will Ix^ more marked than when a greater number of teeth are in action, and the effect of ihc spring will be clearly shown by the waved and uneven condi- tion of ihe surface produced. If, on ibe other hand, the teeth are arranged spirally iliey will come into and leave the work gradti* ally, thus avoiding shock and, what is very important, give a shearing cut. Plain milling cutters with nicked teeth, an example of which I FKi. 463 A. FIG. 463B. shown in Fig. 463 B, are especially adapterm of continuous tooth. When provided with teeth on their faces, these cutters become what are called radial face, side or straddle mills. When the FIG. 464. FIG. 465. teeth are on hut one face and the cutters used for straddle work, they must be cut right and left, as otherwise one cutler would rim backward. The cutler shown in Fig. 464 can l>e run in either direction, as it has teeth on both faces, and constitutes the form usnally used. These cutters, wlieii worked in pairs, and espe- cially for shoulder work, as shown hi Fig. 465. ^jhould be care* fully ground to the same diameter 338 3ilODERS MACHINE SHOP Tl»LS- Tlie end or shank milling cutter shown in Fig. 466 is viitialr ly a radial mill of small diameter provided with its oia*ii mtk- pendent shank. These cutters are seldom made larger than i^i inches in diameter. Their form permits the small diamctcfH which are so necessary in much of the fine milling work. Thrte cutters are made right and left handed, and frequently the icea on the circumference are cut spirally* as shown, siraiglit ti however, being most used. The advantage of the spiral tooth the end mill when used as an axial cutter arises from the FIG. 466, creased shuck and vibration due to the steady shearing c^ which reduces the tendency of the tool to jar loose in the sfii die or collet bearing. The direction of the spiral must be sn that the end thrust of the cutting pressure tends to force shank into, rather than draw it out, of its bearing. In a rigfl band mill the angle of the spiral would l>e left-handed If it is desired to mill a slot with the end of the shank cmi4 shown in Fig. 466. which does not start at the edge of the wc a hole must be drilled into the work of a diameter at least eqt FIG. 467. to the diameter of the space without teeth in the end of the cuttc as otherwise the cutter could be made to enter only a depth equal to the depth of this space, and could not then be mov^ along the work. A form uf cutter shown in Fig. 467 overco this difficulty, as the inner ends of the radial teeth are provici with cutting edges, which enables them to cut their way out wh6 moved along the work. The lengili of these cutting edges limits, however, the depth to which the cutter may be made to enter the work at any one setting. In this Umn of cutter a smalli tuimljer of teeth must be used. The end mill may be plac MILUNC MACHINE CUTTERS. 359 W-~ nc der either of the two first classes, as it may be used for ma- chining surfaces which are cither parallel with or at right angles the axis of rotalton. The standard T-slot cutter is shown in Fig. 468. This tool is used in cutting the slots, a section of which is shown in Fig. 469, the central portion of the slot having been previously removed. In the cutter shown, alternate teeth cut on the inner and outer edges. These face teeth, however, have little work to du, and are PIG* 46S* some cutters omitted, the faces being ground slightly dishing, provide the necessary clearance, T-sIoi cutters are made 1-32 an inch over size in diameter, to allow for grinding. They re usually made left-hand, as shown in the figure* In Fig. 470 is shown an angular cutter. These cutters are us- ally provided with face teeth, as shown in the figure* For traight work the face teeth may be omitted, the face being round slightly concave. When the character of the work re- ^ nc. 469. FIG* 470. FIG, 471. qinres the cutter tu he used as an end mill a threaded hole is substituted for the plain one and the cutter held on the end of a suitable screw arbor. These cutters are regularly made with 40, 45, 50, 60, 70 or 80 degree angles, either right or left-handed. In all of the cutters above referred to, the teeth are sharjKncd by grinding from their top edges, and since the surfaces niillcLl are either planes or wa the crmtour of the surface litietl is nt.t rhanf j ihe cutter. Jn form mill- 340 MODERN MACHINE SHOP TLS. ing, however, the teeth, if so ground, would lose their otitrto and would therefore not produce correct work after being sliii]^^ ened. This difficulty is overcome by the use of the formed ciit- ter, an exajnple of which is shown in Fig. 471. This cutter U sharpened by grinding from tlie front face. A, of each tuoili. The cross-section of each tooth is the same from front to baci. faces. The hack face, B, being somewhat nearer the cenier uf the cutter than face A, provides the necessary tooth clearatict The sharpening of this cutter simply reduces slightly its diam'_ etcr, which has no effect nn the contour of the machined surfac the cutter 1)eing adjusted for depth after each grinding- Tlie original application of this method of forming the ttt^t: ' was on gear cutters, but it has since been adapted to nearh ill FfG. 472. classes of irregular outline cutters used for form milling. Fig.. 4J2 shows at A a new gear cutter and at B a similar cutter* which! has finished complete, at one cut in cast iron» gear teeth aggre-J gating a total length of 7472 feet, the necessary grinding to kcepi the cutter in proper working condition having reduced the teedij to the shape shown in the figure. The last tooth cut was. how- ever, cjuite as accurate in form as the first. In Fig. 473 is shown a group of formed milling cutters. The*] names of these cutters, as given below, refer to the special class ^ of work each is L>. cutters may be made from the first milling cutter it proilucS^ These cutters are made on the end of a bar of steel and arc thin at the cutting end as stren^h will permit their being made* Take, for example, the gear cutter A, Fig. 472. It is fir blanked to nearly the exact dimensions, the spaces which scpar-^ ate the teeth cut and the blank secured on a rigid arbor, whicli is driven in a special machine at a slow rate of rotation. Ifl front of the blank is mounted the outlining cutter in such a ma ner that it is given a small in-anilout motion once per revoltij tion for every tooth to be cut. When the cutter begins to cu at the face A, it is farthest from the center of the blank, and the tooth advances to the face B, the cutter moves toward thd center, thus cutting the tooth deeper at B than at A. While th^ blank is turning through the space to the next tooth the cuttc FIG. 476. backs quickly to its outer position and repeats its motion for ead tooth, until all are properly formed. Relieved tooth cutters are made from solid stock as large seven inches in diameter and six inches in length. It is usua rto make these large cutters in sections, as shown in Fig. 47^ Such combinations of cutters are termed gang mills, and majj frequently be made up largely of standard cutters. In the on^ shown, only the middle section is a formed cutter, the balanc^ being regular stock cutters. What is known as the fly cutter is the simplest of the forme mills, and makes a cutter well adapted to small jobs of spccia work, where the expense of a regular form cutter would not h warranted. The fly cutter consists of a single toolh mounted in an arbor. In making the cutting tooth the stock is set slightly back from the center, and is then turned in a lathe to the desired outline, tempered and reset in the arbor, this time with a lincij iK^hind it, which throws it forward until the front face comt radial, and gives the tooth the desired clearanc' MILLING MACilIXE CUTTERS. 345 As already indicated , the inserted tooth is virtually the only lical method of making very large milling cntters. The prin> Tpal difference in cutters of this class lies in the form of tooth id the method of securing it in the head. Inserted tooth cnt- necessarily have fewer teeth per inch of circumference than lid cutters. This, however, is considered by many as an ad- Intage. It certainly is on some classes of work, as when too many are used the cut per tooth is too fine* the metal being scraped rather than cut away, which produces excessive friction with a tendency to glaze the surface and rapidly dull the cutter. In Fig. 477 is shown a form of axial milling cutter, which is used for heavy slaliliing work. It is made in any required size and constitutes a very efficient tool for heavy work. The teeth re round pieces of tempered steel driven firmly into the soft FIG. 477- >re, and then ground in place. It is found that cutters of this ass do smoother and hctter work when the teeth are irregu- ^rly spaced. A radial mill constructed along these same lines shown in Fig. 478, Here the teeth are held in position by set rew^s, and may he adjusted out when much worn. A plain psk may be substituted for the armed head, the set screws put the back and more cutters used if desired. The cutting edges the teeth should project beyond the circumference as well as he face of the disk. Cutters of this character are fref|uently made of very large diameter. Fig. 479 illustrates an inserted tooth plain milb in which the eth are nicked. The teeth are arranged spirally, and the method of securing them in the head is apparent. The makers of this cutter also make plain solid milling cutters with the divided tooth. Fig. 480 shows a pair of mills, quite similar in construction, in 344 MODERN \IACI11KE SHOP TOOl^ which the tapered pins spread the stock an amoaiit suffidou ta grip firmly the teeth. In the cutter shown in Fig. 481 ilie tedir are pinched in their seats by drawing down with the screws tiie FIG* 47a FIG. 479- VIQ. 480> KIG. 48t, FIG, 482, Fit;, 483, tapered btishings. This cutter is a form of large end mill to carried on a special arbor. In Fig, 482 is shown a shell end mill- ing cutter. End mills larger than i>4 inches diameter are made ill this form with either straight or spirallflttL^The liolc is| MILLING MACHINE CUTTERS. 345 parallel, the drive coming on a key which engages the keyway cut across the butt of the mill. The inserted tooth is well adapted for use in cutters that must be kept up to fixed dimensions, as the teeth when dull can be set out and reground to the exact required dimensions. When in radial cutters of the class shown in Fig. 464 a fixed thickness must be maintained, they are made as shown in Fig. 483 and known as interlocking cutters. 'After each grinding it is necessary to put thin washers between the sections to make up for the reduction in thickness, due to the grinding. With large built-up cutters, interlocking sections are generally used where fixed widths must be maintained. The diameter of a milling cutter should be as small as the work will permit. The small cutter requires less power to drive it, cuts smoother, keeps sharp longer, makes its cut on a shorter length of feed than a large cutter, and is lower in first cost. FMain or axial cutters can usually be of small diameter as the cut is seldom deep, and the surface machined requires length rather than diameter of cutter. This is, however, reversed in the face or radial mill, where the diameter of cutter depends entirely on the width of the surface to be milled. Milling cutters are usually made with the front faces of the teeth radial, thus giving no angle of rake. The angle of clear- ance should be about 3 degrees ; the width of the top of the tooth being, before the first grinding, from .02 to .04 of an inch wide. Too much stress cannot be laid on the importance of keeping milling cutters sharp, and especially the formed cutters. When a cutter starts to dull it begins to crush and remove by abrasion rather than cut the stock. This produces excessive friction be- tween the teeth and work, and unless the cutter is ground promptly, its edges will be entirely lost. In the case of a formeii cutter, when dull, a few revolutions will often so badly snub the teeth that a fourth or even more of each tooth will be ground away before their perfect section is reached. This is a tedious process, and unless great care is exercised is very apt to result in destroying the temper on one or more of the teeth. The grinding of formed cutters requires an emery wheel of thin, dished section with a straight face at the edge. The tendency is to grind too much from the outer part of the tooth face, thus making a negative rake angle and poor cutting teeth. For grinding the ordinary form of tooth, a thin wheel of quite large MODERK MACIONE SHDP TOOLS. diameter should be used. If the diameter is small the top of the tooth will be ground concave to such an extent thai the cutting edge will be materially weakened. By so mounting the wtied that its axis is not parallel with that of the cutter it will grind the top of the tooth flat. This is not ordinarily done* howci'cr. Tlie emer>' wheel used for this purpose should be a free cutting one, and not too fine* as a fine wheel glazes and burns the delicate edge of the t(K3th. Its grinding face should be thin« and the emery al>out Xo. 80. Milling cutters are driven from the machine spindle in ihm ways. Large cutters are frequently threaded directly to the nost of the spindle- This constitutes a most rigid and very satij* factor)' drive. Tliey may also be carried on stub arbors, winch FIG, 484* are either a part of or separate from the cutter, and lastly, upon through arbors, which may l)e supported on the outer end. The small cutters of the end mill class are usually provided with a taper shank and a tang for driving, as shown, for example. in Fig, 468. The Brown Sc Shaqie tafier of J4 inch per foot h the taper usually given the shanks. These shanks fit either di- rectly in the spinclJe bearing of ihe machme or in the collets whidi serve as reducers. In Fig. 484 are shown tw^o examples of milling nii ^ ' i lets. The one drives from a tang, the other from a tlai i^ which engages in a slot cut across the nose of the spindle. collets are quite similar to drill sleeves. Examples of stub arbors are shown in Fig. 4' end mill arbor shown at A is used to carr\ cutit ; shown in Fig. 482 with parallel holes. The * has a tafiered nose and drives the cutter by tin cutter is driven tightly on the nose of Tlie-t MILLIXG MACHINE CUTTERS. 347 rew in the end prevents it from working loose. The nut shown runs over a fine pitch thread and h used for forcing the cutter off. CtUters of the class shown in Fig, 481 are usually carried on an arbor uf this character. In the case of milling cutters with threaded holes, a screw arlx>r must be used. If the cutter is of small tliameter and the work it performs light, a plain threaded nose which allows the cutter to screw up squarely against a FIG. 485* shoulder is satisfactory. If, however, the cutter is large and its work heavy it will tighten so hard that difficulty is experienced in starting it loose. In cases of this kind an arhor similar to the one shown in Fig. 486 is wtII suited, Tlie cutter screws onto the nose of the arhor at A, B is a clutch collar which slides on the arlK)r and over a feather key D, which prevents it from rotat* ing, E E is a nut which threads over the collar of the arbor. FIG. 486. applying the cutter the nut E E is screw^ed close up to the lioulder and the dutch collar slid back as far as possible. The utter U - ' ^'* ' ' touches the keys C C» which are Dan oi V seats in the back face of the C, and the clutch collar nut E E is backed up irmly. In removing the nut and draw^ back the •^- uao&L^ UMitnsr snnr TrmLsi dtrtrh, thti» ka^-it^ the cattcf a^^ ^ • ium -iT, Threaded tcrt, when left-handid ^ould hai r Icft-haml ihrcatlcd hoks mi when right 'handed should haw right-hand threads in the bole, Fia. 4S7. as ochcmHsc the pressure of the cut w*ill tend to toosoi the cutter from its arbor. In Fig. 487 is shown a sprini^^ chuck collet Uj^ed on the mill* PH.. 48S. ing machine for hoUliiig small cutters having parallel ^hank^; example of such a cutler being shown in Fig. 488 Milling machine cutter arbors, an example of wluch is ^huwiT in I'ig. 489. arc fitted to the spindle bearings and driven in FIG, 489 same manner .i^ ,1* . ollcts. The extended portion of the art grcmntl L-ylindrically true and provided with a nut at or neari outer end for clamping the cutter between the washers, "" arliur washers are of assorted lengths in order to acconir MILLING MACHINE CUTTERS. 349 cutters of diflferent thickness. When the overhanging arm sup- ports the bar at the end, a suitable bearing is provided on the end of the arbor. For supporting the bar midway in its length, a collar somewhat larger in diameter than the others fits a suit- able bushing in the overhanging arm. Arbor nuts should be right or left-handed, depending upon the direction of rotation, as a slipping cutter should tend tq tighten rather than loosen the nut. Cutters of small diameter can usually be driven by the friction between washers and cutters alone. Larger sizes, how- ever, should be keyed to the arbor and for this purpose a spline is cut the full length of the arbor. In putting collets and arbors in their bearings in the spindle, both surfaces should be wiped clean and dry and driven snugly together. A soft hammer or block of hard wood should always be used to drive with. CHAPTER XXV. MILLING MACHINE WORK. Dividing a circle into equal parts by means of the plain or universal spiral head on the milling machine is known as "index- ing/' When the index plate is secured to the spindle as at C, Fig. 448, and the divisions obtained by rotating the plate and spindle together, it is' known as direct indexing. When the spindle is rotated by means of suitable geared connections and the index plate remains normally stationary the term indirect index- ing is usually applied. The indirect method can be classified under three heads, simple, compound and differential. Since, as shown in Fig. 448, forty turns of the crank J and worm A are required to make one turn of the spindle the follow- ing rule for simple indirect indexing may be g^ven. Take 40 as the numerator and the required number of divisions as the denominator, and reduce. Thus, it is required to cut 32 teeth in a gear. 40-32, or i 8-32 of one revolution of the crank will make one division on the blank. The sector should be set to include 8 spaces (9 holes) on the ^2 circle, or 4 spaces on the 16 circle could be used. If 108 teeth were required, then 40-108 = 20-54= 10-27, or 10 spaces on the 2/ circle would give the required division. This ratio is not affected by multiplying or dividing both numerator and de- nominator by the same number. Therefore after reducing as low as possible, if that denominator does not correspond to the number of holes in any circle available, we can multiply or divide it by any number that would give us the proper number. also treating the numerator in the same manner. For example. 25 divisions require 40-25 = i 3-5 turns. We can use any circle (livisil)le by 5, as 20, or 4 times the denominator. Multiplying the numerator by 4 also, gives 12 holes in the 20 circle. It frequently becomes necessary to divide a circle into a num- ber of parts which can not be obtained in the regular manner because a circle of the required number of holes is not on the index plate. If a circle for making one-half the required di- visions is on the plate, every other tooih can be cut ; the work can then be rotated through one-half of one space and the bal- MILLING MACHINE WORK. 351 ance of the teeth cut. Thus if 96 teeth are required and no circle available, set for cutting 48 teeth, which gives 10 spaces in the 12 circle or 15 spaces in the 18 circle. After cutting once around, move the pin through 73^ spaces, and being careful that it is not moved, cut partly through on the tooth; stop the ma- chine without throwing out the feed and carefully adjust the driver to make up for the ^ space, which brings the pin into another hole, and proceed with the cutting as for the first half. With care in the adjustment, the error in making the Yi setting will be slight. A method of compound indexing can be used to excellent ad- vantage for obtaining with the regular plates many divisions that may not be had in the regular manner. The application of this method requires plates with the holes drilled through, and the back pin R, Fig. 448, radially adjustable. The method con- sists in indexing forward on the front side of the plate in the regu- lar manner and adding to or subtracting from this movement an- other movement indexed from the back side of the plate. From tables calculated by W. Gribbons and given complete in "Con- struction and Use of Milling Machines," a treatise published by the Brown & Sharpe Mfg. Co. "Jo divide into 91 parts, index forward, on the front of the plate, six spaces on the 39 circle; then index forward on the back of the plate, 14 spaces on the 6 14 2 14 98 -h 183 280 40 '49 circle. This gives — h = h — = = = — 39 49 13 49 637 637 91 or the equivalent of 40 holes in a 91 circle. If 99 spaces are required, index forward 15 spaces on the 2^ circle and backward ^5 5 5 S 5 spaces on the 33 circle. This gives = = 27 33 9 33 165—45 120 40 = = — , or- the equivalent of 40 holes in a 99 297 297 99 circle. For the two cases above given the method is exact. For a large number of the divisions practically possible the method is approximate. For example, to divide into 212 parts. 34-47 turns fonp ^m^ of a turn forward gives 211.9995 teeth, a &% nirate for all practical purposes. In t '•essively cut, 17 turns of the work all of the divisions. 352 MODERN MACHINE SHOP TOOLS. The above method is unique and will frequently be found of' great value. Care must be exercised in making the moves* ^ the chances for mistakes are great, esiiecially so as the t.i plate moves necessitates counting the holes each time* a ^^ not being provided. The new method of differential indexing, as applied by ilir Brown & Sharpc Mfg. Co. to all their universal spiral heads, u an exact method which not only overcomes the chances of enm in the compound method, but is much more convenient. The spiral head is shown in Fig. 490, also in sectional views m Fig. 448, Referring to these figures, an extended shaft fnjitj the spindle carries a gear E, which through the idler D and the FItt. 490. gear C communicates the motion of the spindle to the gear train Fig. 449, connected with the index plate L When pin l\ FigJ^ 448, engages a hole in the plate the whole becomes a locke mechanism. Withdrawing P unlocks the mechanism and tb rotation of the crank J, worm A and spindle causes index plate to rotate either right or left handed, depending on whether on^ idler, D, or two are used, and the amount of motion relative the crank is governed by the gears used. If gears E and C are of the same diameter, nne turn of ihc spindle will make one turn of the index plate. This will rcquir 40 turns of the crank J and as the rotation, due to using ond idler, is in the same direction, the pin P has passed a given poinl on the index, but 39 times, thus giving 39 as the spacing numberJ MILLING MACHINE WORK. 353 Had two idlers been used the rotation would have been in oppo- site directions and 41 would have been the spacing number inas- much as the plate has gained a crank rotation. The manufacturers furnish a complete table of change gears for dividing all numbers up to 360. Take for example the division 317 — referring to the table — gear 64 should be used on the worm C, and gear 24 on the spindle E, with one idler. The ratio of worm to spindle rotation is |J = % and as the plate and crank ro- tate in the same direction, the spindle loses }i of one revolution for every 40 revolutions of the crank, or 3 full revolutions in 320 turns of the crank giving 317 as the number of divisions. Set the sector to give % turn of the crank, or 3 spaces on the 24 circle. When the required ratio would give gears too large or too small in diameters they are compounded, thus keeping diameters within reasonable limits. Spirals cannot be cut when the head is geared for differential indexing. For correct indexing there should be no slack or back lash in any of the parts. It is advisable, however, not to carry the crank and its pin past the hole, but to bring it up to the hole without the necessity of carrying it back, which would serve to let any slack affect the accuracy of the division. It is advisable, in order to prevent confusion, for the operator always to rotate the crank in the same direction, unless there is some special rea- son for doing otherwise. The radial arms of the sector are held in position with refer- ence to each other, by friction. In rotating them over the face of the plate, always take hold of the arm that strikes the pin, as there will then be no danger of changing their relative position through striking the pin with considerable force. In Fig. 491 is shown an end view of the dividing head, de- scribed in Fig. 448, secured on the end of the work table. The spindle S carries a spiral gear at its farther end, meshing with the upper spiral gear shown in Fig. 449. The gear marked **screw" is keyed to the feed screw and through the compound idlers transmits its motion to the gear on worm and through the spirals and spur gear connection to the worm and worm gear. When the spindle is so geared the post R is disengaged from the a*<» and the worm shaft is driven from the dividing plate through '^ And the crank J. It is obvious that when the feed , the plate I is held without the pin R and the re- 354 MODERN MACHINE SHOP TOOLS. quired divisions obtained by carrying the crank over the plate in the usual manner. With all universal machines a table of change gears is pro- vided for determining the proper gears to use for producing a large number of spirals of diflferent pitch. Any desired pitch of spiral can be obtained by making special gears, and a good many pitches not given in the table may be produced by other combi- nations of the regular gears than those given. The proper gear FiCi. 491. for a required spiral pitch may be readily determined from the followinj:^ considerations. The tabic lead or feed screws usually have four threads per inch. Assuminj^ that number, if the gear of the screw had the same number of teeth as the one on the spindle S and was geared directly with it (that is, simple, not compound geared), then 40 turns of the screw would make 40 turns of the worm and one of tlie spindle; and as four turns of the screw are required per inch of the tal)le motion, the pitch of the spiral would be 10 inches. If a spiral pitch of 6 inches was required, 6 x 4 = 24, MILLING MACHINE WORK. 355 the number of revolutions the screw must make while the work rotates through one revolution. Then the ratio 24 teeth in driven gear 40 teeth in driving gear Put gear with 40 teeth on the screw and gear with 24 teeth on the spindle S. It is best when possible to use the simple gearing. If, however, the ratio is such that one of the gears would be extremely large or small, then the gearing should be compounded. For example, required pitch of spiral 32^ inches; 32^ X 4 = 130, or the revolutions of the screw per revolution of the work 130 No. teeth in driven gear 40 No. teeth in driving gear As 130 would be a rather large gear and probably not furnished with the machine we could reduce the ratio to|^, but this would also give numbers of teeth not usually furnished. It would then be necessary to compound. Resolve the ratio ^^ into fac- tors-ij^xV- -^s these numbers are too low we can multiply both numerator and denominator by the same number, and we would have, for example, V" ^ i = M ^"^ ^ ^ i "= M ^"^ ^^ M X U = the ratio ^^ we may use gears 40 and 52 as the driven gears. Either 20 or 32 can be placed on the screw and the other will be the inside gear on the stud. Either the 40 or 52 can be put on the worm shaft S and the other will be the outside gear on the stud. If any of the gears called for were not found in- the regular set, the numbers could be changed by treating both numerator and denominator without changing the ratio. Thus in the last problem, if the last set did not contain a gear of 20 teeth, we could divide both numerator and denomi- nator by a common factor and multiply the results by a number that would give numbers corresponding to available gears. Thus in the ratio |^ divide both by 5 = f and multiply both by 6. This would give If , which alters the numbers but does not change the ratio. In this manner it is usually possible to so manipulate the ratios that the exact or a very close approximation to the re- quired pitch can be obtained with the regular gears. The arrangement shown in Fig. 449 gives the proper rotation for cutting a right-hand spiral. If a left-hand spiral is required a reverse gear must be put into the series. This gear is carried on a suitable arm, and the gear marked 40 drives 72 through this 356 MODERN MACHINE SHOP TOOL3. gear, thus changing the direction of rotation of the wonn and spindle. In the cutting of all spirak the work table must be set a i angle with the cutter's axis, an amount eqtial to the spiral of the work. For equal pitch of spiral this angle varies wA diameter of the work; the larger the diameter the greater angle. In the cutting of any spiral the pitch of the spiral, the spint) angle, the number of teeth and the form of the cutter nmstkl known. Having this data, the work is placed between ccntn and the cutter brought over its center. The proper change gen for giving the required pitch are adjusted and the table swtn| toward the column the amount of the spiral angle. The roll- tion of the. spindle must be left-handed for left-handed spiiris, and right-handed for right-handed spirals, this change in di- rection of rotating being obtained by puttings in or taking oat an idle gear in the change gear mechanism. The proper rotative speeds and feeds are very important as they are the principal factors upon which the output of the machine defx^nds. As the toughness and hardne^ of the differ* ent grades of the several metals varies so much, it is impos»Uc to lay down any fixed rules to be followed. With cutters other than the most delicate the very fine feeds are to be avoided, as the cuttings edj^es stand up better under a moderately heavy cm than when scraping the metal away. Millinjr cutters must Ik» kept sharp. As soon as a cutter loses its keen cutting edges it dulls very quickly and does not proilucc smooth or accurate surfaces as it springs away from its work. A cutter must not be run backward when against its cut. as the teeth are not strong against a backing pressure and are apt to bo broken off. rOr the standard carl)on steel milling cutters, a surface speed of 30 to 40 feet per minute can be maintained on soft machiner>' steel, thoroughly annealed tool steel and wrought iron. In such cases, however, the cutters should be sharp and lubricated with screw cutting oil or some good compound. On cast iron cutting speeds of from 40 to fio feet per minute can be maintained, de- pcMiilinj:^ on the hardness of the iron. On brass a speed of from 80 to 100 feet per minute is sm'table. These speeds may. with cutters made of special air hardening steels, be materially in- Teased. MILLING MACHINE WORK. 357 The depth of cut and rate of feed employed are dependent lupon the hardness of the metal, its strength to resist the cut, rigidity with which it is held, and character of finished surface required. In general finishing cuts with plain axial mills are taken at quick speeds and fine feeds. With radial mills finishing cuts may be taken at coarse feeds, as the character of the cut due to tbe long cutting edge, does not show a waved or uneven sur- face. In the case of expensive gangs of cutters, and more especially on those where fixed dimensions necessitate great care in grind- ing, it is advisable to hold the cutting speed down somewhat. The following table will be found convenient for determin- ing the proper number of revolutions for cutters of different diameter to give cutting speeds up to 60 feet per minute. TABLE OF CUTTING SPEEDS. F««t Iter MiDnt«. 5' 10' 15' 20' 25' 30' 1 35' 40' j 45' 50' 60 TXam. REVOLUTIONJ 3 PER MINU' rE. ^ 38.2 76.4 114.6 152.9 191. 1 229.3 267.5 305.7 344.0 382.2 458.7 H 30.6 61.2 9T.8 122.5 153. 1 183.7 214.3 244.9 275-5 306.1 367.5 H 25-4 50.8 76.3 IOI.7 127.1 152.5 178.0 203.4 228.8 254.2 305.1 ^ 21.8 43.6 65.5 87.3 109. 1 130.9 152.7 174.5 196.3 218.9 261.9 I 19.1 38.2 57.3 76.4 95.5 1 14.6 133.8 152.9 172.0 191. 1 229.2 ^% 17.0 34.0 51.0 68.0 85.0 102.0 1 19.0 136.0 153.0 170.0 204.0 ^H 15-3 30.6 45.8 61.2 76.3 91.8 106.9 122.5 137.4 1 53. 1 183.6 iH 13.9 27.8 41.7 55.6 69.5 83.3 97-2 III. I 125.0 138.9 166.8 iy2 12.7 25.4 38.2 50.8 63.7 76.3 89.2 101.7 114.6 127.1 152.4 iH 11.8 23.5 35.0 47.0 58.8 70.5 82.2 93-9 105.7 117.4 141.0 1^4 10.9 21.8 32.7 43.6 54-5 65.5 76.4 87.3 98.2 109. 1 130.8 iH 10.2 20.4 30.6 40.7 50.9 61. 1 71.3 81.5 91.9 101.9 122. 1 2 9.6 19.1 28.7 38.2 47.8 57.3 66.9 76.4 86.0 95.5 114.6 2}4 8.5 17.0 25.4 34.0 42.4 51.0 59-4 68.0 76.2 85.0 102.0 2% 7.6 15-3 22.9 30.6 38.2 45.8 53-5 61.2 68.8 76.3 91.8 ^H 6.9 139 20.8 27.8 34.7 41.7 48.6 55.6 62.5 69.5 83.4 3 6.4 12.7 19.1 25.5 31.8 38.2 44.6 51.0 57-3 63.7 76.5 3K 5.5 10.9 16.4 21.8 27.3 32.7 38.2 43-6 49.1 54.5 65.4 4 4.8 9.6 14.3 19. 1 23.9 28.7 33.4 38.2 43.0 47.8 57.3 A}4 4.2 8.5 12.7 16.9 21.2 25.4 29.6 34.0 38.1 42.4 50.7 5 3-8 7.6 II-5 15.3 19. 1 22.9 26.7 30.6 34.4 38.2 45.9 SVz 3.5 6.9 10.4 13-9 17.4 20.8 24.3 27.8 31.3 34.7 41.7 6 3.2 6.4 9.6 12.7 159 19.1 22.3 25-5 28.7 31.8 38.1 7 2.7 5.5 8.1 10.9 13.6 16.4 19.1 21.8 24.6 27.3 32.7 8 2.4 4.8 7.2 9.6 11.9 14.3 16.7 19.1 21. 1 23.9 28.8 9 2.1 4.2 6.4 8.5 10.6 12.7 149 17.0 19.1 21.2 25.5 10 1-9 3.8 5.7 7.6 9.6 II. 5 13-4 15.3 17.2 19. 1 1 22.8 The smaller milling cutters which are carried on an arbor are usually driven by the friction between their faces and the arbor collars. They should therefore be rotated in the direction 3S8 MODERN MACHINE SHOP TOOLS. which lends to tighten the arbor nut. With the large which are keyed lo the arbor the direction of rotation may! either way, For a given rotation of the cisiier tlie dir the feed should lie such as lo force the work against t as shown at A, Fig. 492, When the rotation and feed sat\ above indicated, alt slack or hack lash between tlie nut and fc screw is taken up and the work is forced steadily to its cm, li% the feed is as shown at R, the cutter tends to drag: the work mio it and as a result any slack whatever allow^s the work to m'-'^ forward with an unsteady, irregular motion as the feed sctr^ rotates. When the feed is as shown at A* the cutter teeth wok from the bottom up. lifting the hard scale of castin^^s ancl fire ings rather than cutting down upon it, as is the case uliLn ^ I'U. 4^^ feed IS as sliown at B. The keen edge ot the cutter lasts mffl longer witli the feed in the direction intlicated at A. The undc feed indicated at B has been advocated by some, but is gcnerall; considered as incorrect, as the wear on the culler and the dange of accident from the work drawing under is much greater. Will milling machines using the rack feed where the work table is he only when the feed is in. the most careful workman wilt soni^ times get into trouble if the under feed B is used. When the cutter is operating on the end of the work sliown at D. the feed should be up. as indicated by the arrowj if the work was on the other side of the cutter, the feed shoul be down. In this class of milling it is best to feed up. as t\v brings the pressure of the cut down upon the table and tends close the joints of the table* saddle and knee, making the ct smooth and steadv. When the table is to be fed verticallv fc MILLING MACHINE WORK. 359 ^ work as shown at D, the. table stops, provided with all milling * machines, should be used and thus prevent any possibility of the ' work moving in or away from the cutter when' correctly set. ■ When it is necessary to use both sides of the cutter at the same time, as in Fig. 493, the direction of the feed should be deter- mined from a consideration of the amount of stock to be re- moved from the sides. If the rotation of the cutter is as indicated and the most stock is to be removed from the surface A, then the feed should be in the direction shown by the arrow. The cut on the upper surface then tends to retard the feed and the cut on the lower surface to draw the feed: and since the cut on the upper surface is heavier than that on the lower, the re- tarding pressure is greater than the drawing, and a smooth, steady cut results, with a minimum danger of injury to the I FIG. 493. work and cutter. If the cut was heaviest at the surface B, the cutter should be started from the opposite end and the direc- tion of the feed reversed. Plain surfaces may usually be milled either by the plain axial milling cutter or a radial or end mill. The axial cutter leaves a smoother surface and is more easily kept in order than the radial. The tendency to spring and distort the work is, however, greater with the axial cutter, as the pressure of the cut is very largely at right angles to the work surface, while with the end mill the pressure is almost wholly in the direction of the feed. The character of the work usually determines which class of cutter to use. At i and 2, Fig. 494, are shown two ways of milling a common hexagon nut. The straddle mills of No. 2 are radial cutters and, as arranged, finish two surfaces each time over the work. An end mill might be used, in which case but one surface would be finished at a time. In any case the diameter of the mill should be as small as strength and con- vr^ M'jder.v machin'e shop tools. I ■■ -r.r^r.-Te a ill p^rrmit. An inspection of Fig. 495 shows the r-;i-' r: :' r thi*. ft the ponion D E F G of the work is to \-/t r-rr.. -.r'i r,\ the cutter, it is evident that the smaller cutler X taiK\' A. If tho wichh \V of the work is -^niall. tlu' saviiii,^ in time reiinircd for the work by usinj^ the vinall viitter heconus a ciiisiderahle portion of the total time. MILLING MACHINE WORK. 361 The first cost of the smaller cutter is less and the power required to drive it also less than with the large cutter. In placing cutters on the arbor, the faces of the cutter and the arbor collars should be carefully wiped and thus insure a true running cutter. As shown in Fig. 496, a small piece of cutting or dirt A between the faces, causes a spring in the arlx)r and the cutter will run out of true. When made, the faces of these collars are carefully brought parallel with each other and, with reasonable care, they can be kept in this condi- tion. When, as in 2 and 3, Fig. 494, two cutters are to be used for straddle work, it is necessary when the distance between E / / FIG. 495. FIG. 496. the faces of the work is to be of exact dimension, to have collars of suitable length. As the regular collars usually make up by eighths above one-fourth inch, suitable washers must be pro- vided for making up the exact dimension. These may be had with parallel faces and varying in thickness by .001 -inch, thus making it possible to obtain any desired dimension between the faces of the cutters. When it is required to machine the top surface of the w^ork, a plain axial cutter can be used between the straddle mills in place of the collars and washers. At 4, Fig. 494, is shown the final operation in the milling of a T-slot. The neck of the slot and all the metal possible should If^ be snc fgnioigd widi a pini axial cimcr« as in Icvg, 497, whidi >aTe» a rtimiimiTii amoom of work lor the more delicate T-skt csrter :«: pertocm. If the natore of the woiic is such that a plain cotter canocc be oscd. the stock can be removed with an coA mill In tfab case, a cutter somewhat smaller in diameter than the reqiiircd width of the neck most be used first, as the spring of so small a cnner when taking such a heavy cut woaU cause the work to be ontnie. The neck can then be finished to exact width bv passii^ a siziiig' cotter throogfa or by trinuning each side with a finishxng cm with the roaghiiig cutter. The null- ing of a \*-slot. 5. Fig. 494. is sinnlar to that of the T-slot, the most of the stock preferably being first removed with a phin cutter cr an end mill. The cuncr shown could he used to com- plete the work at once, without the use of a stocldiig cutter as It is provided with teeth on its shank. This is not, however, the -le FIG. 497. piCf. 498. PIG. 499- customary method, as the necks of these cutters are not usually provided with teeth and the spring of the cutter makes smooth, accurate results very hard to obtain. At 6, Fig. 494, is illustrated a method of milling^ the guides of a housing. With a cutter of proper thickness and diameter, both sides and bottom of the guides are finished at one cut. This figure serves to suggest one of many similar operations that can be performed with a plain cutter. No. 7, Fig. 494, shows how the milling machine can be used for boring and facing work. The work is clamped to the table of the machine and a short boring bar placed in the spindle bearing. If the hole to be bored is of considerable length and diameter, the outer end of the bar should be formed to fit the bearing of the overhanging arm. thus making it firm and capable of producing .1 smiM^»»^ ♦•-Me bore. An automatic in-and-out feed is very de- : of this character. It will also be noted that the MILLING MACHINE WORK, 363 ^prerticai and lateral adjustments to the work table enable the work ^Bto be set in any desired position for the boring of parallel holes. | ^Kl*akep for example, the piece of work shown in Fig. 498, where ^■Ihe two holes are to be bored parallel with each other. The ^Jwork should be first squared up and the hole A bored ; after B-which, by means of the graduated elevating screw, the w*ork can Hie dropped exactly ijis inches and by means of the graduated ^Bfeed screw set over the 4,V4 inches, which brings the center of ■ the hole B into exactly the proper position for boring. In like H^^^"ner any desired nimiber of settings may be obtained quickly and with great accuracy* In making setting measurements by the use of the graduated screws precaution must be taken to < avoid the error that might arise from neglecting to consider the^ Hback lasli between the screw and its nut. Thus, if a vertical ad- justment is to be made, the table for tlie first operation should be dropped a little tCM> low and brought up to the proper point. I The index can then be set at zero and the work table raised the exact amount required by the graduated screw. If by accident the table is raised too high, it shotild be lowered somewhat below the proper point and again brought up to the correct reading. This insures against any error arising from the back lash and means that in all settings the slack between the nut and screw ■ should be kept on the same side. | A long tool with cutting edge at right angles to the boring bar may be used for facing off the end of the work after the ■ boring operation. The end next to the spindle can. of course, be faced with an end mill if desired, or a facing attachment con- sisting of a slide and twjl-carrying heanfiray is to tic ott in the shaft at toaic poini between the cod*, to receive a Jibrirt key or femther. ibr eiid mill i» o^edL If tk mill h not of thr cenicr-cut tvpe a Mnall lide^ ai Elile larger thai Ihr djanicirr of the toothless center of the caXMa^ Aoald k ffriller] at one end ami to ;i ' ' ! to Ibe 4. shows the method of flutinj^ a reamer. The present example isi that of a tajHT reamer. In this case the tail center is raised an amcnmt sufficient to ^vc the proper depth of cut at each end tif the flutes. The cutters usually employed lor this work arc specially formed cutters aucl should be set so that the face i>f t!ie cutter that cuts the front face of the tooth stands on a radial lia^^UkMlHIIlMdg Fluted, as shown in Fig. 499. MILLING MACHINE WORK. 365 No. 10, Fig. 494, shows the method of cutting spur gears in the plain or universal milling machine. One or more of the gear blanks are mounted on a mandrel and placed between the centers, the gear cutter having been previously placed on the arbor and the table adjusted in and out so the center of the cutter falls in the line of the work centers. The index is set to g^ve the correct number of divisions and the work elevated until the rotating cutter just touches the rim of the gear blank. The graduated dial on the elevating screw is then set to zero, the work moved out from under the cutter and raised an amount equal to the required depth of the tooth. Spur gears too large to swing between centers can often be cut by placing the index head spindle in a vertical position and carrying the blank on a vertical mandrel held in the spindle. This places the blank in a horizontal plane and the cutter is set to depth by the table feed screw and the work fed to the cutter by the vertical feed. In Fig. 500 is shown a method of cutting a large spur gear in a plain milling machine using a plain dividing head clamped to a knee plate. The gear shown is 30 inches in diameter. The greatest care must be taken in an operation of this kind as the leverage on the spindle of the dividing head is considerable and the chances of shifting the work great, especially if the cutter is a little dull. By previously gashing the work with a plain cut- ter, the chances for a true job are very materially improved. Another method of cutting large spur gears in the milling machine is illustrated in Fig. 501. This is known as the under cutting method which is accomplished by raising the dividing head and tail stock by means of suitable elevating blocks and providing a substantial outer support for the milling arbor. An adjustable post in the tail stock raising block can be brought to bear against the rim of the blank immediately over the cutter, thus taking the cutter thrust and relieving the centers of this strain. The fluting of the tap shown at Xo. 11 is similar in all respects to the fluting of the reamer in Xo. 9. Xo. 12 shows tlu- method of bobbing a worm gear, the blank having been pre- viously gashed. The hob is a cutter of exactly the same shape as the worm that is to mesh with the gear and sim])ly forms out the teeth, the blank rotating free on the centers. In gashing the teeth of the worm gear before bobbing, it is placed on the ma^ le an amount C D E, Fig. 502, deiH^iding upon tbej \ and diameter of the worm. The work is then raised to the < ler the proj>er aitioimt and dropped for each succeedtn^^ If the !hri*ad of the worm wheel i.^ id he right -handed, the tabic i FIG. 501. swivelcd to the rij^ht, and to the left if left-handed. For the bin^» the bed is set hack to zero. Bevel and miter jjears may be cut in either the plain or imi versal milling machines when e(|iupped with an elevating^ indi head. The teeth so cut are of approximate outline, but sufli^ ciently exact for all ordinary uses, As shown in Fig. 503. t gear blank is mounted on a suitabk- mandrel held in the chucl or, as shown, fitted to the spindle bearing of the elevating heai The head is then elevated until the root line of the tooth i MILLING MACHINE WORK. 367 -'jMuallel with the work table. The proper cutter for the particu- ^iar pitch and number of teeth is placed on the cutter arbor — and brought central with the work. : For any pitch the depth and width at the outer end of the tooth is the '• same as for spur gears. As the inner end of the space is narrower, the cut- c__ ters for bevel gears must be thinner --g" than for spur gears. The index hav- - ing been set for the proper number of teeth a few center cuts are taken. The index pin is then advanced a few holes and the work moved out a few thousandths from the central position . ^i^- 502. and the cutter again passed through the spaces already cut. This should remove some of the stock from the side of the teeth, taking more at the outer end than at FIG. 503. the inner end. The index pin is next carried back double the number of holes it was advanced and the work moved in double 368 MODERN MACHINE SHOP TOOLS, the amount it had been moved out for the previous cut, Tbb throws the cut on the opposite side of the tooth. As there \s m fixed rule for the amount of these settings, the tooth must l»f measured and if not of proper thickness another trial sctiiug mu^t be taken. When tlie proper settings are found for any particular gear, they should be noted for future reference. The center Oit * is then not necessary as the tooth i*^ finished b_\ the two side cut*. In Fig. 504 is shown a method of cutting bevel gears in a plain millm^ machine using a plain dividing head A splinf is milled in the face of the knee plate at the proper angle to 'l^ r^^^^^H .-V - -- ^' ^^^^^^^^^^^^^^^^^^^M FIG. 504. receive the tongues in the base of the licad thus fixing thei cutting angle, A separate spline must be provided for caclij angle of gear cut. When a large variety of gears* necessitating! ka number of different angles, are to be cut a plain graduated I 1 plate pivoted to the face of the knee plate and carrying thcJ dividing head gives all angles. Where a grackiated swivel IVaseJ vise, as shown in Fig. 45 T, is available, it can be used to excel- lent advantage in cutting the sphnes in tlie knee plate at the re* quired angle. The method of cutting a twist drill in the universal miltingj machine is illustrated in Fig. 505. The settings are as forj cutting a spiral gear, with this difference, that the depth ol MILLING MACHINE WORK. 3^>9 ;,,flyte in a twi^t drill should be less at the shank end than f\^ PQ\nt. It is therefore necessary to elevate the point sonic- When the flute is to be cut from the very end of the ik, the shank must be held in a chuck on the spindle of the FIG. 505. universal head, and for the outer end, supported on a suitable steady rest. If, however, the work can be carried on centers and the cutter dropped into its cut as close to the point as pos- sible, better results can usually be obtained with less liability to accident. In this case, the head spindle can be dropped a few FIG. 506. deg^rees below the horizontal position, or the tail center raised to ^ve the proper taper to the web of the drill. The backing oflF of the lands of the drill, as shown in V']^. 506. is a somewhat difficult operation, requiring good judgment on the part of the operator. Tilt* work lalile i* swttnjEj throogfi a eait'tl liy thu liiu* r a. which causes the t!jid mill tt# cm i c than at c, thus clearing the lip, a» slif>%ni in tht end i^ii^. 5^. rits. 5cA Figs. 507, 508 and 5139 show exampit:> *h machine work. In Fig* 307 the end nnD in ilic on the tfvsidci s^Tiaot tsl. % \«e3 lAa^^ 37-' MOUKRN MACIllXK SllOl' TOOLS. until the jaw touches the ar1x)r. If the contact is iinifonn ilic full length of the jaw, the setting is correct. This prc-su|}|)^'-vN a true running arbor. Squaring from the front face of lik- column with an accurate square is equally satisfactory and thj better method if the arbor is not dead true. For the 90 or down. It also insures, on w(^rk of equal diameter, the sanu' hciglit of setting, a very im])ortant condition, which is difficn't to obtain with certainty when the work is allowed to rest on llu- face of the vise slide, or on a ])arallcl. lu)r nuich special w rk fal^o vise jaws can be used to very excellent advantage as tlu-y may be formed to irregidar contours oi either work nr cinur. ^" J"i^. 511 i'*^ shown an exam})k' of heavy gang milling, in tliis case the seats for caps and quarter b(^x cheaks are rinisl:e The advantages of tntllin^ this piece of work over jjhnuvi^ it. 4'IG. 511. Sc in the pussihi lilies fur |>crfcct duplicatinii in the fornK-r, as |^ell as the time saving element, it being milled in approximately ;)ne- third the time required fur planing. In Fig. 512, is shown the stock, false vise jaws in which it is FIG. <^i>. leld and gang of cutters for the finishing the tool steel piece phown. The stock has had a screw machine operation upon it L'forc coming to the luiih'ng machine. A suitahle stop on one of MOimKN MACHINK SMOI* TfX)LS. the jaws Ioeaie!i the work in the vise with reference to the tiirwd shouliler. Tlie jaws are hardened with rouf^hcd surfaa*^ in: finnly j:rMM*^*'K '^^^ stock* and a copious >up|ily of luhr used on the work an millintr. In ihb I *G. 513. iSb the ji^^ cnnsi>ts uf a plate secured to the work table ui ilk* machine and a second plate pivi)ted to it. Hie work which ha^ been previously bored and faced on its lower side fits over a projeclii)n on (lie upper plate which boMs it concentric witli tlir pivot. The work is sqiiaretl up and the face mill machines one of the spots. The work is then rotated ibrough ip degrees, deter- mined by a pair of ^oii pins, and the second spot machineil. The pair of straddle mills shown are next used to fah*>\\ n iii \'\'Z :• •liiirk. whicli i> "f i ' :« r i.f tlif riittrr ani , - i^rij). tlu- cam '.Mi;'.r.«- Ml. I Niiiii .! \ li-.un. tlu' ci-nKM" "f ll- Mil ll nil ill. ,|i.| I,., ll,,. tir t nr nuii^hini;' <-"'■■ '■' •''■'■ Mi.lil till li.W.I I, It ,.l vUv vwWv'X WWcVw- \V-i MILLING MACHINE WORK. 177 Center line a a of the work. This roughs down one of the straight sides of the cam. Next rotate the chuck slowly by means of the worm and gear until the cutter has roughed all the sur- face around to the point b. Ky next dropping the work, the other FIG. 516. straight side is milled. As machined the two straight sides wijl be flat but the circular portion will be somewhat concave, due to the high position of the cutter. For the finishing cut the cutter should be set with its center at the height of the work center. FIG. 5 1 6a. This brings all of the work on the end of the cutter which leaves a straight surface, but does not cut as freely as when for roughing. This class of work brings considerable strain wcnr oil the worm and gear of the dividing head. 3/8 MOUEKN MACHINE SHOP TCX>LS. Cutter vibration can usually be traced to some slack in tabte joints or spindle Ijcarinf^. Heavy cuts on frail work are apt to chatter. Straight cutter teeth are much more apt to cause chatter than spiral ones. A harmonic relation between the numbers of teeth in the back gears and the number in the cutter, when thr machine is running in back gear, is without doubt a frequent cause of chattering. The graduated dials on all table feed screws are of g^rcai value in setting cutters in the proper position relative to the work. Hiey should, when possible, he used for 'making these settings, care always l)eing exercised in taking up the slack or back lash in the screws. In the milling of steel and wrought iron a cutter^ lubricant is used. I^rd oil is generally considered the best for this pur- ]><)se. although its high cost often precludes its usfe some form of compound l)eing substituted. Many of the soap and soda com- poimds are very good substitutes. The object of lubrication is to suj)ply. not only enough of the lubricant to keep down friction, but enough to cairy away the heat of friction and thus preserve the cutting edijes and make possible higher cuttinf; speeds. Cast iron and brass do not require a lubricant. (^istinj^^s that are to W milled should be free from sand and har. It is th running gears are required, the ])lanin,i^ j)rocess is used. The tren era tint:; of conjugate tooth outlines, or in other temi.s, the forming of the teeth upon cylinders that will cause them to r<»ll together as the pitch circle of the one would roll upon the ])itch circle of the other without slipping, is a condition that can only he obtained by a molding process. When two newly cut gears run together, a molding process takes place, the high parts wearing down and gradually pRxhic- ing a sni(K)th running conjugate tooth. \i vW \5i.^\.Vv o.^ ow'c^ ^g^s». GEAR CLTTERS AND GEAR CUTTING. 381 ^iircrc covered with fine file-like teeth it would quickly mold the -^vteeth of the other gear. r. The forming of teeth in this manner by a process known as ^ the molding-planing process has but recently been put into a / practical form for spur gear cutting in the Fellows gear shaper. The single-tooth molding-planing process, as applied in the Bilgrim machine, generates conjugate teeth on miter an^ bevel sear blanks. The making of formed gear cutters involves the laying out of the templet and making of the negative cutting tool as descril^ed in connection with Fig. 472. As the tooth outline varies with the number of teeth in the gear a cutter can be made exactly correct for but one number of teeth. In practice, however, the outline varies so slightly, espe- cially for the larger numbers of teeth, that one cutter, although exactly correct for but one number of teeth, is used for cutting quite a range of numbers. As the tooth outline changes very rapidly for the lower numbers of teeth the range is small for these numbers. In the involute system the permissible range is much wider than in the cycloidal system. In the following table is given the numbers and range of Brown & Sharpe involute gear cutters : No. I will cut wheels from 135 teeth to " 2 " 3 " 4 " 5 "6 " 8 " " " 12 " •* 13 " In cases where a finer division is required in the number of teeth to be cut with each cutter, as sometimes occurs when very smooth running gears are required, intermediate cutters between those regularly used may be had on special order. The range of these cutters is given in the following table : 35 teeth to a rack. 55 •* 134 teeth 35 " 54 " 26 *' 34 " 21 25 " 17 " 20 " 14 " 16 " No. of Cutter. Range. No. of Cutter. Range. ^H 80 to 134 teeth. 5"^ 19 to 20 teeth. >«2' 42 " 54 " 6'.^ 15 *♦ 16 " i\4 30" 34 " iVi 13 A'i 23 " 25 " 382 MODKRX MACHINE SHOP TCK)I-S. In the cycloidal system 24 cutters are required for cutting all numbers from 12 teeth to a rack as given in the following tal»k: Cnttcr A cuts 12 teeth. ] Cutter M cuts 27 10 29 tetil B cuts 13 " •* X cuts 30 to 33 "' •' C cuts 14 " •« 0 cuts 34 to 37 * 1) cuts 15 *' " P cuts 38 to 4-* * E cuts 16 *• " Q culs 43 to 49 •• F cut> 17 " i« R cuts 50 to 59 " G cuts 18 •* " S cuts 60 to 74 H cuts i() ** •• T cuts 75 to 99 *' 1 cuts 20 (( I' cuts 100 to 149 •' *' J cuts 21 to 22 " ** V cuts J 50 to 240 *• " ■ K cut> ^3 to 24 " " \V cuts 250 or more. L culs •^5 to 26 •• " X culs Raok. For bevel .crear cutting, involute teeth, eight cutlers havini: the same range as alxn-e given are required. These cutters «i"rtir from those used f(^r s])ur gearing in that they are considerably thinner, a condition made necessary by the cutters having to pas? through the narrow end of the tooth space. The regular 1>evol FIG. SiS. gear cutters are thin enough to pass through the narrow end of the space where the length of the tooth is not more than i-^^ the dis- tance from the outer end of the tooth to the point at which the axes intersect. Where an extra length of tooth is required, an especially thin cutter must be used. Cutters for spur gears have the pitch and the range of teeth stamped on them. Cutters for bevel gears have the pitch, but nox the range stamped on them, inasmuch as the range does not or- dinarily correspond to that given for spur gears. The selecting of GIL*\K LL TIERS AND f;lSAR CTTTING, 1c proper cutter for a spur gear is therefore a simple matter, ks it is only necessary to know tlie iliametral pitch and the number pf teeth. With bevel gears, however* the following considerations re necessary. In any pair of bevel gears lay off the back cone aciius a, b for the gear, and b, c fur the pinion^ Fig, 518, Con- sidering the gear, r is the actual pitch radius and upon which le pitch and number of teeth depend. The outline of the tooth. jlowever. is tlie same as for a spur gear, having a radius a. b. Pake, for example, r as equal to 4 niches, and assume Xo. 6 iametral pitch, which would give 48 teeth in the gear, rcfjuiring, it was a spur gear, cutter No, 3, The hack cone radius a* h leasures 8 inches, requiring a tooth outline the same as a spur FIG, STQ. FIG. 520. ir of gb teeth, or cutter No. 2. which would be the correct cut- ler to use. In Fig. 519 is shown the Gould & Eherhardt duplex gang ^ear cutter, which consists of two or more cutters mounted to- gether and of such diameters and forms as to cut and correctly inish two or more teeth at each passage through the blank. An [inspection of the figure shows the central cutter to be of normal diameter and symmetrical with reference to a central plane. The [side cutters are somewhat larger in diameter and the center line of the front face of each tooth is coincident with a radius of the B blank. It is evident that but one diameter of gear can be cut with each gang, and the larger the diameter of the blank for a given 584 MODERN ITACHINE SHOP TOOLS. pitch, the more cutters it is possible to mount in one This condition at once makes the gang a purely manui vkA, which can be advantageously adapted only in cases lar^e numbers of each size of gears are to be cut. In using AckI gangs, care must be exercised in setting to the exact depth of oi 1 and that the blanks are of exact diameter, as inaccuracies k these conditions will produce thick or thin teeth. These cutters are ground from the front face without chang- ing their form. With these gangs as many as ten finished teeth may lie cut at one passage through. the blank. Under ordinary conditions the excessive heat generated by the removing of » much stock necessitates a somewhat slower rate of feed and cnttcr rotation than can be employed with single cutters. A jet of com- pressed air directed against the work and cutters makes possible much hijjhcr speeds. The Clough duplex cutter, as shown in Fig^. 520, although a form of ^ang cutter, finishes but one tooth at a time. The object of ihis cutter is to protluce gears having a widely different number of teeth, that will interchange with a single cutter. Correct tooth outline must of necessity 1)c sacrificed in accomplishing this end. dears cut, however, with these cutters fim fairly well t(^ether an' much lower o<»^t. In I'ij;. 3JI is shown an automatic gear cutter capable of cnttinj^ spur j^ears only uj) to 40 inches in diameter by 9 inches face. In I'ij^. ^22 is shown an automatic gear cutter for cutting lx>th spur and bevel j^ears up to 18 inches diameter by 4 inches face. In these machines all movements are entirely automatic. The work is secured to the dividinjjf head spindle; the necessary change f^ear adjustments made for dividinjj the work; the work set to the cutter so as to cm the proper depth of tooth, the correct cutter having: previously been put on the cutter spindle, and the machine started up. '*'" ^ in the cutter advances 386 MODERN MACHINE SHOP TOOLS. at any angle between a horizontal and a vertical posiBoa. with the cutting of bevel gear in the milling machine, the ( must pass twice through each space, the automatic features di machine, however, remaining the same as for spur gear cut&i|. Due to their smoothness of action, spiral g^ears runniif in d1 are largely used for driving the cutter spindle. As the center d1 the cutter must, for spur gear cutting, be under the center of dt i work and as the cutters vary in thickness, it is necessary to gin the spindle an adjustment endwise and to provide a suitable gauge for setting the cutter central. The feed to the cutter slide on the machines shown is accom- plished by a slow rotation of the feed screw, which rate can be varied within necessary limits by a change of gearing. The auto- matic disengaging by stops of the clutch, which engages the for- ward driving gear with the feed screw, stops the feed. The same iiiovcnicnt engages the screw with a qoick-running reverse gear which brings the slide back very rapidly. The changes from the one iiKn-cinent to the other occur without pause or shock. The exactness with which the dividing mechanism performs its work is deiwndent upon an accurately cut worm gear and worm: accurately cut change gears; nicely fitting- bearings and adjustments permitting of no l)ack lash; and an escapement mov^ nient vvliich allows the locking disc-shaft to make exactly one revolulion. or, as is the case with the Brown & Sharpe machines, two or tour revolutions at the time the division is made. In theuld be employed, using the same change gears. Where work of small diameter is operated upon, the outer end of the work mandrel is supported by an overhanging arm and no further support is necessary. If of large diameter the end of the mandrel is carried in an outboard support, and a rim support steadies the blank immediately back of the cutter. In setting the work to depth it should be lowered until the revolving cutter just touches the circumference, and the dial on the elevating screw then set at zero. It should then be dropped the required amount for the cut by passing somewhat beyond the required distance and turning up to the mark, thus avoiding any error due to back lash in screw and connections. Gear cutting machines when used on steel gears are provided with an oil pump for supplying a liberal amount of screw cutting oil on cutter and work. In the cutting of steel gears, when prop- erly lubricated, a high rotative cutter speed with very fine feeds are usually advisable. The lubricant prevents the heating of the cutter and the fine feed overcomes its tendency to "hog" into the work. The cutting of bevel gears in the automatic machine shown in Fig. 522 does not differ materially from the milling machine method described in connection with Fig. 503. The side mov 3as MUDIIkN MACIUXK SHOP TOOLS, mcnt is given ihc catter rather than the work, and the same a and judgment must be exercised in making the prcliminar) set- tings. In the culling of heavy pitch and steel bevel gear>. h til usually advisable to make a center cut, thus necessitating iWa^ cuts for each tooth. The cutting of racks may be accomphshed in the milling rna- chine by use of a special attachment* as sliown in Fig. 458: m the automatic gear cutter by means of a suitable attachment FIG. 524. on a special automatic rack cutting machine. An attachment the automatic gear cutter is shown in Mg. 524. A cross rail secured to the front of tlie upright » atid this is mounted on a slidj ing head with provisions for"clamping the rack blank on its tmdc surface. A pinion on tlie nose of the dividing spindle engages rack on the head, thus making it possible to automatically mo\1 the bead the correct spacing for each passage of the cutter throug the l>lank. ^lancj cutters can be advantageously used in racM cutting. All cutters must be of exacth the same diameter aii ited on the arbcr with their ccmers the exact pitch dbiauKe Japan. \Mierc larg» anxnints uf rack are tu lie cut, machines for [tfiai special clas;? of wc»rk are cmployeiL The Fcliows gear shaper. aba%*e referred to, is shown in Fig, [525. The cut Ulusirates a from viei^ of the inachiiie ai work on internal gear. Hk' cuncrs arc tltustratcil tti I- ig. 5JC1, ami itie thotl of securing them to the cutter :*piiHlle b shown in I'ig. jr C_ FIG. 525. 527. \s already stated the ciiiicr is a cnrrectly f*irmetl ^'ear dij^lie*! on thecutung face in order to give it an angle of rake. The ctUti^, altlinugh rescmhiitig a s]mr gear, is in reality a Wvel gear, having a very small center angle. Tins feaiiire gives the cutter the ncre^- sar> clearance in the work. Ijion the correct forming of the cntter fiei>entls the accuracy of the work produced on thi*» macfrtnc. Since the side of the tooth of an involute rack is a siraiglit line* the sulisiitution of the face of a cutting wheel for the side of the »0 uufir^tM UAcniye suoi* iools. fi^B^m kFtf» ^rr. GEAR CLTTEkS AND GEAR CUTTING. 391 lLth would by the molding process produce a correct involute <:>utline on the tooth of any gear that, meshing with the rack, was ^raused to pass this cutting face. Upon this fact is based the ^nethod by which the Fellows cutter is finished. The cutter hav- ing been planed from a blank, as shown in Fig. 528, and hard- ened, is put on a special grinding machine and the tooth outlines ground to the correct form, the operating of the machine depend- ing upon the principle above explained and clearly illustrateil in ^^S' 529. The rack, of which the face of the wheel forms the side of one tooth, is a fixed imaginary oiie and the cutter blank is g^ven, by a suitable mechanism, a true rack and pinion motion CUTTER BLANK FIG. 528. past the face of the emery wheel, which grinds the sides of the teeth, one at a time, to the correct form. In its operation the cutter and blank are so geared together that they rotate the same as two complete gears in proper mesh. After starting the machine, the cutter is fed toward the blank until it has cut the exact depth of the tooth. Rotation which cor- responds to a feed then begins, a small amount at the hej^inning of each stroke, when the cutter is clear of the work and coniinues until the cutting is finished. The method of holding the w'ork is shown in Fig. 527. a suita- ble face-plate and clamp with a work sui)])ort in connection with the draw stroke on the cutter making a very rigid combination. When the character of the work necessitates it. the cut can be 39^ MODERN' MACHINE SHOP TOOLS. taken on the down stroke, such usually being the case when cutting internal gears. The stroke of the cutter ram is adjustable, as to length and position. Since the teeth of the cutter are conjugate to the generatii^ rack, all gears cut with the cutter are conjugate to it and to each evel gears having the octoidal form of teeth are cut theoreti- E^arWhtti ] Cutter riG. 529. cally correct by a molding planing process in the Bilgram bevel gear platKT. Fig. 530. The generating tool has a straight cutting Qd^c and is given a ni(nion parallel with the root of the tooth and constantly moving toward the a])ex of the pitch cone. In this machine the gear blank is given a rolling motion as it swings under the cutting tool. This motion is accomplished by means of a pair of bands wrai)ped about a portion of a conical laving its apex in the intersection of the axis, upon lie hlaiik is inountetl aiul the pivotal axis of the head. The ncnts of the macliine are such that the motion given the s the same as it wouhl receive if it was rolling in gear with lar rack. As the cutting of the tool corresponds to the t side of the rack tooth, its action is to generate a conjugate m the blank. The inilexing mechanism spaces the teeth I feed rotates the hlank slightly for each stroke of the cutter. ,hc cutting of worm gears by the bobbing process is illus- I I method uf procUicing conjugate teeth by a rotating cutter. r)eration as performed on the universal milling machine is ed in comieclion with 12 Fig, 494 and big. 502. machines designed specially for bobbing work and known bing machines, the work spindle and hob are geared to- by means of a suitable system of change gears, thus driv- ? work blank at tlu^ proper speed relative to the cutter 1, With machines of this class it is not necessary to i»re- e blank by gashing, as the gearing insures correct spacing* lelhod is clearly shown in Fig- 5^^i. which illustrates the T attachment for rhe bobbing of worm ^ears on a ylain 394 MOUERX MACUIXE SHOP TiX>LS. milling machiiK-. As dearly shown a pattern womi on the work 5|jititlle, having the same number of teeth as required on the woric, gears with the hob. Spiral gears are usually cut in the universal milling madiine with a formed disk cutter moimted on the regular cutter arbof, or preferably on the sipnidle of a universal milling attachnienL as shown in Fig. 454. In the laiu-r ease ilu- setting for ibe spiral angle is made by swhiging the auxiliary cutler arbor 10 i\vc re<]uired angular ptisition v^hich is a ver>^ desirable feature in llie cutting of short pitch spirals. As is the case with the teeth of bevel gears, spiral gfear teeth can be formed tlieoretically correct b) a plaiiing process in whicb Pia. 531, the cutting tool is given a rolling feed that causes it to follow llie outline of the tooth, the work being rotated as it advances u> the tool at the proper rate to produce the required spiral. The teeth may also be correctly formed by using a planing tO(jl of the same outline as the normal t(Hjth space* the blank bc»r^g again rotated to produce the proper sj^ral Teeih of spiral gears in which the spiral angle is great, as in a worm, are usually formed by this method in a screw cutting lathe. As the planing process is necessarily an expensive one. the more rapiil %et less accurate met bod of milling is usually used. Fc.r this method two forms of cutters are use strictly drilling work. As a manufacturing tool, it is. however. due to its simplicity, the readiness with which it can be ganged, and its comparatively low cost, rapidly growing in favor. In Fig. 532 is shown a standard pattern upright drill. This is a back geared machine, the back gear mechanism being inclosod in the upper horizontal spindle cone. This gives the spindle eight speeds. The. spindle has a three-speed automatic feed witli an automatic stop for knocking the ii.'^i\ off at any rccjuired i)osition of the spindle. Roth wheel and lever feeds are also i)njvi(led with a provision for quickly moving the spindle when the worm on band wheel is disengaged from its gear. The rack and i^inion method of moving the spindle is common to practically all makes and styles of drilling machine. The spindle has its lower bearing in a ([uill which is given a close sliding fit in the head. The tVed rack is secured to the quill. The machine shown is of the sliding l^ead patteni. the head having a vertical adjustment on the front face of the column to adapt the machine to work of different heights and drills and tools of varying lengths. The head is counter weighted by an equivalent weight on the inside of the column and Ilimpffd in any po«ition. For work too high to be fitipf I hi* ttiljMMnlilt* ubir, Ihr lower hase table is used Hfi it " icIiidL*^ «jf 11116 i!l:i^<^. a statioiiar} head iilltKi*%' uncnt |icinf( ^ivcfn the tallied. M;ichiii fMMMi||HUil*c rri^ulnrly made tip to 5a inches cap| mIm» iflOlriftmtf Ahi- iiuivutmni cruitneter of work, the center] II ilrilU« a tight machine should hcl r3er to obtain the high speed required ant I the lijjhtness of parts ecessary to make the machine sensitive. l*y the term sensitive, applied to small drilling machines, is commonly imderstood tliat Hfjhtness of parts, smooth rumiijig and perfect balance which enables the operator to judge as to the pressure he is applying to the drill and consequently lessen the danger of drill breakage. In addition to the above features some builders go a little farther and employ at some point in the drive an adjustable friction which can be so set as to just flrive the drill being used. Tn I'ig. 533 is shown a simple and efficient friction driven sen- v'K' 533^ t'lt*'- 534. sitive drill The frictton driver is adjustable to compensate for wear only. The speeil of the spindle is varied by the position of the driving frictiun wheeL In Fig. 534 is shown an example of a very heavy upright drill- ing machine. This machine is designed for very heavy work, as the boring and tapping of tlanges. It is of massive proportions and powerfully geared. When, as illustrated in Fig. 535, a number of drilling spindles are driven from one main spirullc. the machine is known as a mul- tiple spindle drill. In the drill shown, the spindles can be set at any desired position within the limiting circle. This is a manu- '>m»n»rn I»;im' ami driven either inclepcnwrtm* ir ilicy arv ktJtmu as gang drills. Tiicy anil an manufacturing tools arc coming. * i<»nr-s|ji!ulle ]4*iiich ^ang it long enough from time to time to lake out le finished piece and put in another. When so operated the tiin- ig should be so arranged, if jjossilde, that all spindles except the ne at which the work is lx*ing changed are working. The automatic feed and feed knock off are quite necessary for Jie latter class of operations. When work of larg:e diameter is to be drilled near its cen tit ffir imrtic lUf FIG. 537A. I»» liilmtltutnl f(ir ilu' unial cone pulley. By means of a lev <'|»i*rai)ii^: friiti«»n rlutcbc**, fiihcr of (cnir ^|icccls m;iy lie iiisum uhialiKMl. The back gear. %\hich is niQunud un tlic butt ui «rrn» in «*<» arrati«c*l that four speed changes arc obtained, til Hivhii^ 4i\tt'ru s\)vvi{ cliaujre* for the spitidle, all of which are i riiu^ed in ^vutuciVKikl pro^re?^!*ion, Reversal of tlic spindle rolj Hon fitr Uiiiping I* aceoiupliiilied at ihe hea* lar vi|mii^||||^^^^r MiAnipulation. st^ecial attention to ^►CAlb*^ i»eratiug levers is given. ... in what are known as **hair ms. In I lie "halt*' universal radial* DRILLING MACHINES AND nRTLLlNO WORK, 403 drilling spindle is mounted on a svving^in^ frame which allows the spindle to be set at any angle, in a vertical plane, parallel with the face of ihf arm. In the *'fuH" universal radial the arm is pivoted to the hutt in such a manner that its face can be rotated through WL complete revolution, thus making it possible to drill holes at -ariy desired angle with the base* For a large portion of the angular drilling work pul un these Lchincs. the universal drilhng table, Fig. 538. in conneciion HK'.. 538. rith the plain radial machine, is well suited. In this case the B^'ork ratlier than the spindle is set'at the required angle. On classes of work where each ofieration is short, and as a Dnsequcnce it is not economical to attempt to work on more ban one piece at a time, turret head tlriils are well adapted. In fig. 559 is shown a drilling machine of this class. The lurrt-t arrtes a number of spindles which can be successively thrown _inio position. Each s{>indle carries its particular tool for the irork in hanil and only the sfjindle in working position revolves. In Fig. 340 is shown a horizontal spindle drill of radial pal- frn. The value of this class of lool. not only for general work '< imiU.lXG MACHINES .SNh DRILMNG WORK. 405 Suspension and traveling^ drills comprise a special class used 5r the drilling of plates antl nthcr work too large to he handled Itider a radial. The suspension drill is made to bolt to the ceil- ig and the work is moved under it. With the traveling drill he head is mountetl on a steel bridge which is carried on side acks similar to a traveling crane. These machines have the >indles motor driven, and although limited in their vertical ad* istmcnt are capable of wide lateral adjustment, making it possi- Je to reach any part of large heavy work without moving it. Tn Fig, 541 is shown a two spindle gang manufacturers* drill entirely new design and construction. This tool is adapted FIG. 540. ^^p to the requirements of the manufacturing plant having many similar pieces to be drilled. In its action the operator throws in the icQil lever and the spindle instantly advances by a quick movement until the drill comes in contact with the work surface. hen the regular feed starts. When the hole is finished the ipindle automatically returns. It is therefore only necessary for the operator lo put into and remove the work frum the carrying In Fig. 542 is shown a pnrtaltle drill operated by a compressed ^ir motor through the rtexi))Ie shaft. An electric motor or a rope tansmission may be substituted for the compressed air motor 4D6 MODERN MACIttNK SHOr TOOLS, amdiH I MJien desired. In nuiny cases r small air motor is (Ureclly to the drill spindle. When a drilling spindle is to be Uftcd for tapping, it i> nccit*^ sitry thai sotne (jrovisicm he made for reversing the spindle, Vtic DRIT.tJNC MACHINES AND HRUJJXG WORK. 407 >mmon method is by using a double clutch counter shaft with ic open and one crossed drivinjj^ beU. This arrangement causes reversal of all lurnmg parts which is open to some objection. >me builders are employing a geared reversal, either directly the spindle or on the first reducing shaft. In Fig. 54J is lown a combination of three bevel gears for this purpose. Gear IS keyed on the first reducing shaft* gears A and B run loose the spindle, the clutch D is keyed to the shaft, but free to i I ■M r^ FIG. 544^ lide up or down over the key. A suitable lever engages with the liuch, thus making it possible to lock gears B or A with D, cans- pg the spindle 10 rotate forward or back, depending on which tar is made to drive. This makes a very smooth and satisfac- ry working drive. It is frequently necessary lo use small ilrills in a large machine. As the spindle speeds are entirely too slow for the proper running these drills, the high speed clrilling atiachmen* ' n 4oS MODERN MACHINE SHOP TOOLS. be used to very good advantage. The box contains four gc«ir>, one cut on the lower end of the taper spindle, another on the sphidle carrying the drill chuck with the two others mounicti together on the stud shown. The arrangement is precisely likt a back gear with an increasing rather than a decreasing spindle speed. The securing of work on the table of the drilling)^ machine n- quires clamps, bolts, jacks and blocking, the same as for planer and milling macliine work. The same care should also be cxtr- cised in the setting, as true work requires careful setting. Tlie use of the square and surface gauge, and good parallel bars are indispensable in setting up work for drilling. For thnnTi::[h drilling the work must be so located on the table that the drill in passing through will enter a slot or the central hole on ihe table. If the drill is too large or for any other reason this can-" rio, 545. not ho (lone, the work should be placed on parallel bars sufficiently thick to raise the work enough to allow the drill to pass thruui;li without spottinj;" Into the tal)le. riu' work tal)lc should be ke])t in good condition, and to drill a liolc into it should be an tmpardonable offense. As the work tahlc on upright drills turns abotit its center and the table arm turn> on the cohnnn. it is possible to so adjust the table that any point on a piece of work clain])e(l to it can be brought inider the center of the drill. ]u)V drilling surfaces at right angles to a plain surface, the work can be secured to a knee plate or preferably to the table oi a horizontal s])in(lle drill. R(uni(l work can be advantageously clanii)0(l in a ])air of 90 degree \' blocks. 1m )r the holding of small and medium sized pieces of work the drilling vise is much used. In Fig. 545 is shown a form of DRILLING MAt'HINKS AND DRILLING WORK. 409 drilling vise with an angular adjustment to the sliding jaw for holding tapered work. Nearly all pieces of work can be held in some manner in a vise, and in some cases when a large number PIG. 546A. B ]^ :x miW Em I FIG. 546B. of irregular shaped pieces are to be drilled it is found advisable to make special false vise jaws for holding them. In Fig. 546 is shown, at A, a new drilling vise with a cross section at R. The method of operating the sliding jaw in this vise is such as to always hold the jaw tight down to its slide. FIG. 547. which prevents lifting and drawing the work out of true in tight- ening. In Fig. 547 is shown a special jig drilling vise. It consists of a substantially made plain drilling vise with the jig drilling attachment shown. The attachment is secured to the stat.\o\\^.TY 4tn WMXm% M^CMJ«£ i;iH . Jiw pfM C pmsttto a 'vercicad and a iuinuy adtn ih liriMl) £bti»|M9d in ymitkin, Thr yaifir 1^. OTfan af>t it k ttiii alil-.i'« till' TirM f#r»r i» da»i|M9d ia 'dhr riar and -flit aiii|' £ v£ ;i'l)ii»ic'"" II" « ;in Im- ili\iil(«l intu i\vo general classes, plate M • .mil li. .-, ||..s. \ plair iliiPini' jig is one vvhicb can Ik* laid 11. ii njniii til,- sill i;ic,. nf \\\v \\«»rk. ])rnp ibr ban erf Ar ted asd k6 r fii^ vMA b tfOBRd a* Wioc¥« dtts time from Ae dril&ac m- mt ubic In ^ ^^e». after 4r3iB^ thr Itr^ h^Sr. ihr >u^ ?^ ^ (S ^KM 4 ^■y| FIG. 552. i J i) i mn ^[u>u^J be iiiscTtcd in it to prevent ; lihimn^ nn the work. In Fi(f. 552 U shown a fomi m ^ is UHc«<1 ii)Kiti. In this ca^c all tU6J|^H ur ariit t1irc*<« nf them do n(»i i»as&1^^P § 1 DRILLIXC. MACHINES AND DRILLINt; WORK. 413 cl and bored. All holes in the jig are located with reference he bore of the work. The lower portion of the jig holds the k central and the upper portion carries the bushings. These s are nicely fitted together and suitable dowels insure their ays remaining in the required position, relative to each other, the holes that are low on the work surface, extended bush- ; are used. [n Fig. 553 is shown a simple form of box jig used for drill- holes in round work at right angles to each other. The itruction is evident from the cut. The work is slid to a stop the jig and clamped in position. The hole E is drilled )ugh the bushing C, and F is drilled through the bushing D 1 the jig resting on its faces A and B respectively. When angle A () P> is a right angle, the holes will be drilled at right ies with each other. By making the angle A O B any re- •ed angle the same angular relation between the holes drilled result. From a consideration of Fig. 552 it is evident that when holes to be drilled in a piece of work at any angle with each other, "^ can be used. This jig must contain the work and have faces, one to receive the bush and the other to rest •^ble, at right angles to each required hole. »f steel and wrought iron requires lubricatiou 414 MODERN MACHINE SHOP TOOLS. for the cutting tool. Cast iron and brass are drilled dn-. At with other cutting: tools lard oil makes the most satisfactory liin ricant. It is expensive, however, and as a result cheaper rd and (Irillinjy com]K)unds comprise the lubricants most used, .\sthf lubricant a>nducts away the heat of friction generated in the cm- tinj^ of st(Kk, it should be freely applied and provisions made fur (Icliverinji: it to the very cutting edge. This, as previously d^ scril)e(l, is accomplished by means of oil tube drills. These when used in a revolving spindle require a special form of socket wWdi can !>e connected by pipe or tubing with a pump, for forcing the lubricant. The drilling of deep holes is usually accomplished in special drilling machines usinj? pod drills. Long twist drills are noi - i~' -----,f 1 p \.:.:^-,^r^ 0 /I. ■-■-■«. r \ -l I'Ki. 554. will suited to the drilling of deep holes inasmuch as the strain tends to untwist and make ihem vibrate and catch in the work. There is also not sufficient land area to satisfactorily guide the drill, thus making it difficult to drill true, straight deep holes. The poll drill is shown in iMg. 554. It is of semi-circidar cross section, the ladius nf the section being equal to the radiu^^ <>f the re(|nired hole. All the cutting is done by the end face ai A !> which is given the necessary clearance, and I'or drilling steel a small amount of top rake. An oil tul>e 0. hcddid in the shank, supplies the lubricant to the cutting edge. I'or this class of drilling it is usual to rotate the work to a sta- tionary drill. The W\^i\, however, is usually given the drill. For the drilling of dee]) holes of large diameter, the drills used have an inserted cutter which can be removed for grinding and set out to coni])ensate for wear. DRIIJJNt- M \t ni.MS AM) tJNII.LlXr, WORK, Spnttinj:^ anfl fadng of small surfaces is usually accomplished ^ih a cuunter borinfij tool of the class shown in Fig, 555. In iis tool the ciutcr is held in place by the small screw in the end |f the teat. The teat bushings are removable, several sizes, being iniished with each counter bore. For special work it is ad vis* >le to have a separate coimter bore for each piece. They should made of tool steel and the teat or pilot point hardened after the mW 5Sd 3t is finished. A plain mortise through the stock with a small Set screw in the center of the teat is a satisfactory method of holiiing the cutting blade. By reversing the blade this t(X)l is also well suited for back facing operatic»ns. In Fig, 556 is shown the usual method of doing this work. The character of the work is j^uch that the face F cannot be ma- chined from the insire !^» should be made to fit nicely in the hole an- vd : an arm A su])i)orting the tij)per end of the work. The yoke Y is bolted to the table and extends into the work through an openiiii: in the side. Hiis yoke carries a pilot bar P which fits in a tap- ered l)earing at K. The boritii:^ bar i> threads on the nose of thf s|»indle and has a reamed hole H through it to receive the pik)t bar P. The cutters (" (' are se^cured in the end of the bar an! rnugh out the stock at the first passage through the bore. Sizinir rutters are next substituted for C C and the bore brought to reaming size. At the end of this cut the facing cutter V which is secured in the head of the bar, as shown, is carried down and the end oi the cylinder faced by a swee]) cut. The construction of the end of the bar is such that the cut- ters C C and the sizing cutters can be changed without altering DRILLING MACHINES AND DRILLING WORK. 421 ir dimensions. This is especially important with the sizing* ter, as it will carry throupfh several bores without reijrinding. e pilot bar P is now taken out and an inserted blade reamer FIG. 564. nn the end of the boring bar is floated through the bore ^h, round and parallel. *^n the above work comes Itovw \\v^ ^q^ q>^. 422 MODERN MACHINE SHOP TOOLS. the R. F. Barnes Company, and its size retaining features are of special interest. It is shown in Fig. 565. The cutters, one of which is shown at A and B, are inserted in the head, as shown. The shank oi each cutter is tapered and drawn firmly to its seat by the IxdIi shown in B. The cutter disc corresponds to one thread of a coarse pitch square thread screw, a portion of which is ground away, as shown at C. In obtaining the required size, the cut- ters are numbered, hardened and fitted in the head. The head is then placed on a mandrel between centers in the grinding ma- chine and the cutters ground to the circle D D of the exact di- ameter required. They are then removed and each cutter ground FIG. 565. to tlic dianiclcr E K, and replaced in the head, each cutter in it-^ rc'S])octivc boarinj^ as indicated l)y the numbers. This is ini- l)()rtain inasnuicli as the locations of the bearings vary somewhat and C()nse(jnently all the cutters are not of the same diameter. The cnttini^ edj^^^e can l)e set to a line across the face of the head and by i^rindinj.^ from the face X only in sharpening, the exact diameter of the tool can be maintained until the cutters are entirely i,^round away. Uy kee])ing a record of the diameter of each cutter, others can be made at any time without the ne- cessity of the first j.rrindin<^ operation above referred to. The objection to this tool is its comparatively short cutting edges. It is onl\ adaj^ted to reamers of the larirer sizes, as enough cutters cannot be put in a head of small diameter. CHAPTKR XWIIL GRINDING MACHINES AND GRINDING. Grinding operations in the machine shoji (lepenriin4kim. when suitably held and presented to the work. Tlic of the solid 5:rrin(!ing wheel has made it possible lo attain IV refinements in machine construction that would have been FIG. 566* intpossihle without it. h lias made it practical 10 cconomicaJly finish parts in hardened steel that could not ix3ssibly be macliined ng tools in the lathe f»r planer; and on the softer faces smoother and truer can be obtained by grind- ntber methof a rest. Tool and cutter ^rinrhnj^ requires a better class of grinding ichmery than is retpiired for the hand-^rindint: operations. What is here referred to as tools does not include the ordinary hand and lathe Uyoh, commonly e^round nn the machine shown in F»!£C- S^7< hut refers to drills, reamers, millini^ cutters, and the finest class of tools. Fig, 569 illustrates a universal cutter and mo. 563, reamer grinder. As the name implies these tools are provided with all the necessary adjustments and attachments for grinding cutting edges of all classes of reamers and milling cutters, in many cases may be used for doing a hmited amount of idrical grinding both internal anrl external. A nnich simpler show^n in Fig. 570, constitutes a very satisfactory cutler small proportions, Dy the use of the swivel hearl of all angles may be readily ground, and by plac- thc slide which Is opcTated by the lever shown reamers up to the capacity of the machine may ating cutler in machinini,^ opera* ig these cutters true and shari> 4tter grinder whenever this clnss GRIXDINC; MACHINES AND GRINDING. 42; ^f tools are used. In the grinding- of cuttLTs care and jud^nnent pjust be exercised and not nntil the ojK.Tatnr lias become ibor- ajEj^hly familiar with all the setting combinations of tbe machine an he expect to q^et the best results. As water is not used on the wheels of cutter jy^rinders and ic wheels are for this work usually tjuite hard and fine* H^ht cuts i FIG, 570. »^^^j<4^ FIG, 571, ^ust be taken in order not tcc to th* '^•ftimg cdjsje iffin^4 operations involve the removal by a "^11 part of the work sut(^c^, VW ^V\vA* 4^8 MODKRX MACHINE SHOP TOOLS. ing material used Ix^ing of such a fine character as to leave a smooth, hig^hly-finished surface. This class of work is usually clone on the buffing spindle shown in Fig. 568. Bufiing (i(X> not leave a true surface and is consequently confined strictly t> jK^li slung work. The grinding of twist drills is a very particular operatun. requiring a skillful operator, if performed by hand. In Fig. 571 is ^iKAvn a twist-drill grinder in which the twist drills may Ix' gr >und with the assurance that the angle and clearance will W correct and equal on Ixnh sides. In the machine shown, the construction is such that drills of any diameter within the limits of the machine may be ground with but one preliminary adjustment for each size. Unfortunately a twist drill can be ground by hand on a plain emery wheel, which fact keeps the twist drill grinder out of many shoj)s where its use would add materially to the efficiency of the drilling ecjuipment. Correctly ground drills cut faster, stand up longer between grindings and produce the proper size of hole. A correctly-ground drill seldom breaks, as it cuts freely ahead of its feed and does not scrape and jam. as is the case when clear- ance and angle are wrong. (irinding machines for the grinding of common forged lathe and planer tools arc manufactured, and in shops where lari^^^e luimbcrs of forged tools arc used have proved very efficient. In the working of these grinders the tool is clamped in a suitable head and presented to the emery wheel at the proper rake and clearance angles. (yliiidrical grinding as a class, covers all forms of grin da). ^ . - -: ■ rr — ■:... > : ic-r'-ir the jra:n? '.f cnierx . ami in jh- -: ."■: ^~^.*r '.t:-:.'-:': . "^L iT-i lulloi. the} break a\va\ fr.ii!i -..-.•::.- -:"-..-_> - :.-.t -Tr-T-:. \r.-l fresh .:ra:n< arc uno»vcroi t.i .' ^ ." '.."T :--":r^ '. - *:t**. I: ".hi* breakinj^ ».I«>\mi pr-icc^N '^iriV -. -i ;.. ■..--: ■.s'r.i-z'^ ju:? vcr. freel>. but rohico< :ri i T-.T- : .~:*:.' r .i-^J. fi*:. I: :hc ceniert, *m\ ihe other haiM. • r ' r ^" :- :- -J-:^ — ^-n.r* .: cner^. the wheel jrlaze>, cius . i- 1 !::i:* :!:- ■'..-'•. I'ric siirface vel'•: i:~cr-cr.: ':'.a>-k:> •..£ \V'.»rk an«l j^raiU- m* ■-.-:'. I'-T .. '— ! > r iTir.*.;. ri-.>: crncieii: j:;>l l»efore it > " --.i--\: i'.i. ir : .c-^-r? : ^'.^zc. L*p to this ]K.»iii:. the hi|L:lKr '.'. -'K'r\ :::e r • -t * .'.il :: a:!! rer^ivvc m a Jiriven len^jth if *:■ -.. V. rr::. rj:: i: ! .,cr -t-re'i. :: ciit'^ >«.»:r.ewhat easier, nr.il ! ':* r. ' : - i*. :*::-: a r-. as 'a:'.;.. « liazinv: i> u>ually prevenit.! r-rlv-.r^: :'•-.- *:*\::. S :: -.xhevls --rain I \\y l>elter at hi,,li. ': a: .1-. '. . *;-.-.-■.-. 7'"^ Aiivr :hc !av:e> '.f the wheel jireseiiU'l • :;>j v-rk. rre rr. z-: <\i\\\z\,z >-.:rfav:e. arul the faster tlie im::i; * \:z .::•.'. a.'..!.. Th^ :\e :< :t:iisi be corres|Kmvlini:l\ 0'iir<:. .";>. .'. ::-r-:'i:v : v.-.vx.!-* ^r.- \\.\ Ije o »:r.paratively soft, an*! as tlic •i- r ■:•.:'•- :• v.: !*.:•. :::..■ A'xel -^h'-ulil increase in hanlness. '.':■': -■.:':^.^.> <-•'. : :;x w irk shfuM Ik* |>roi><)n innate :■• •■ ' -;••• : ::.■■ v. ::i-r!. ;;•■'. iv. :i::\ case shi»uM Ik' surficietnlx si^w :.'.'. w ::>: wViv. ;t"ip'.v :::'v !•» cut away the meial witlMu: !' '. ii':;^'. Ti- ■ !?•'. rv. :-i :Ve \n« rk i- >;»ninj: away fnmi the wl\ri -•■ -r !«■*-. ;;::■: •.:'::r-.:v -a. -rk re-iull'i. \ free K'wr'v.vj, wlu'vl. r;:!i at the proper spet^l anil with a Iii:lK ••. :- 1m.->i i-r accurate L:rin«iiu^'. a< it removes the metal within' • ••-^••'. a:]'" •-•'ii«»t<;ue!nly cut> tlie hiirh sjkus most anil <1 >vn ■ • li: :.r 'ij; tli( Work. Ii In. Iii iwever. necessary on ver\ accuraii- v. ■^ri. to usf \va!».r '-n the wluel, a> a slij^ht chanjje of tem]Kra- !:n« aflVrt-- tlir w-irk iiotici\'ihl\ . When lonjj^ cuts are ti> he takvu. :t i- -.ii!«tinK-< 'litVuult tn»perly a«lapti.Ml, aii'l « acli ;.:raiii of eiiury nuist ciu as lonjj^ as possible ])cfore tln^p- l)iii.L: out. As tlu- har«liT whei-ls hold the emery lon<^er, and can In run vfunwhat -lower, tluy are best aho'.ild have a wi many i^rains (»f the abrasive as possible GRINDING MACHINES AND GRINDING. 431 to perform the required work. It is also necessary to use the coarser feed and Hght cuts in order that the wheel may cover the entire surface before it drops materially in diameter. The direction of feed is changed for each time over the work, which also tends to even up the wear on the wheel. All manufacturers of grinding wheels, however, give a table of speeds for the different diameter of wheels they manufacture, but these speeds are not always best suited to the work. All wheels should fit easily, yet closely, on their spindle to prevent danger from cracking, and a soft washer of uniform thickness should be placed between the sides of the wheel and the clamp- ing washer. The wheel should be firmly clamped and trued be- fore using. Manufacturers test all wheels by running them at a speed considerably above their rated speed. In the grinding of long work it is quite necessary to support it at one or more points between its end bearings, as otherwise it will spring and chatter, making true smooth work impossible. For this purpose, suitable steady and follow rests are provided with the machine. In Fig. 573 is illustrated the method of grinding slight tapers FIG. 573. 432 MODERN MACHINE SHOP TOOI-S. in the universal or plain grinding machines. By means of a screw and graduation at the end of the table it is swivelcd to the re(|uired angle with the line of travel of the slide. In this man- ner tapers up to lyi or 2 inches per foot may be ground. When a steeper taper is required it can be obtained in the universal ma- chine by setting the wheel slide to the required angle, as shown in I"ig. 574. In this particular case, two tapers, one of 43 de- grees and one of 5 degrees are required on the work. By swing- FIG. 574. in.L,^ tlu' swivel tahlc lo 5 (Ici^rccs from ihc line of its travel the ^lii^lit taper ean he j^rouiul In the travel of the table past the wheel. I»y seltinj^ the wheel slide to ^o dei^rees, as shown, the steej) taper is l^touikI hv operatiiiL;: the wheel slide, the swivel table re- numiiiijL^ statiotiarv. If hut the 45 deivree taper was recjuired, the ta!)Ie would he left erntral, ancl the wheel slide set to 45 degrees. As shown in the ent, the corner of the wheel is dressed to give a enttini^ face of suitahle width. GRINDING MACHINES AND GRINDING. 433 In Fig. 575 is shown the usual method of face grinding. The -work is held in the chuck or on a face plate as shown. If the face is to be a plane surface, the head spindle axis is set at right angles to the wheel spindle. By varying this angle concave or convex, conical surfaces may be obtained. In Fig. 576 is shown the method of grinding internal surfaces Fi^i- 575. with the internal fixture. The example given serves to illustrate, as in Fig. 574, the settings for both slight and steep tapers. The small taper is obtained by setting the swing table to the required angle with the travel of the table slide and the steep taper, by using the wheel slide set to give the wheel the required line of travel. It will be noted that in using the internal grinding fix- ture, the position of the wheel table is reversed from its universal 4J4 MtiOUIN M.\CHIXE SHOT TOOLS. fMfiitirjn aiwf the fixiore Mcnred lo the end of the taUe. A kit. rn^ jack L» sab»ntau«{ ior die emerr wiied spindle and the spindle of :he internal flxtnre drtren by a fight canvas belt from the jad. Ahhoa^ the spowfle of the mtemal grinding fixture is drha a: a vety high speed, the dianxtcrs of the wheels tised are so snail that it b not possible to obtain a periphery spotd as high as woolj FIG. 576. 1)0 clcsircfl. Tt therefore is necessary to use a free cutting wheel and to nnate the work to it at a comparatively slow speed. On these machines all work and wheel settings are to care- fully graduated arcs. These graduations cannot, however, be relied upon for exact settings within the accuracy limit of the machine. If, for example, the machine is set for parallel grind- ing on a certain class of work, the head stock i^ "nped and the spindle thrown out of para''-*^ — -th the to "wd; it will be found practically ii ^ (iRixnixf. M AtHiNi:^ \su nRi\mNG. 435 piginal position, sufficiently close to make the machine gT'm<^ irallel again. In fact, so tnhiute are the variations tliat the wheel ill clt?tect that the unclamping of the tail stock, moving it out of sition and then hack will show an imparallel condition of the ^rk. It therefore hecomes necessary after each setting of head tail stock to readjust the work tahle In- means of the end ad- asting screw in order thai the line of rotation may he brought irallel with the line of motion of the tahle slide* Surface grinding bears the same relation to planing that cyl- PIC. 577. idrical grinding does to turning. The surface grinders use the same form of wheels as the cylindrical grinding machines. The fork, however, is secured to the work table, which is fed under over the wheel. In Fig. 577 is shown a surface grinding ma- chine. The construction of the machine is clearly show^i. The wheel ts adjustable vertically to give depth of cut, the arrange- of pulleys being such as to give constant tension on the all positions of the wheel. The cross feed is obtained the table toward or away from the housings ou suit- 43^^ MODERK MACHINE SHOP TCX^LS. able cross slides. Provisions are made for supplying the wheel when necessary. In I^g. 5/8 is shown a plain jEfrinder [jroviilefl with a iBrS grinding plate. Tn this case the wheel projects alxjve the stirj of the plate only the amoiini of the cut required, and the wc passed over it by hand. To give satisfactory restdts, the %pm and its bearing shoidd be ftrst class, and the wheel in fKrrtcct I ance, A gamier of ilus class is a most satisfactory tool smoothing and i>i3lishing surfaces vvlierc finish am^ rrquirt'd, A m*>re rcfmed grinder. ^tHnt-wliat :i order, and known as a disc grinder is shown n are very nicely constructed grinders in whi^ ' done by sheet emery gluetl U) the f.icrs ni tli< swing across the face of the disc. ik being I' the rest. For the finishing - ' ^ " plane small parts, this tool is very \ URIKDING MACHINES AND GRINDING. 437 111 Fig. 580 is shown a iorm of porlahlc liaiid tinery grinder iven by a rope iraiisniissioii tlirough a llt'xiblc shaft. These inders are very satisfactory tools for the grinding of heavy b^tings that cannot be held to a wlieel. For Iruitig the emery wheels used on the better classes of rinding machinery nothing Inn a black (hamond truer is suitable. >uch a tn<\l is shown in Fig. 58 l The diamond is mounterl in fie end uf the mund sieel htjider. as shown. The round holder FIG. 579 bles the stone to be presenter! to the wheel in various iK)si- ^hit as tci bring the several cutting points of the stone into Ah t!ir diamoufj is harder than the emerv% it aclnallv cuts ^ure is usually |)rovidcd for holding the truer I it can be passed squarely by the part of the Iter should be tised on the wheel in true- lit^fht in order to obtain go<3LS. shown in Fig. 582 are used. Several forms of discs arc used. The discs arc made of hard steel or chilled iron and turn freely upon a pin. In their action the teeth of the discs break up the surface of the wheel as they roll together and dislodge the high particles of. the wheel by a picking action. lapping is a refined grinding process used for the final finish- ing of machine ground surfaces, usually of hardened steel. A lap is usually made of cast iron, copper or lead, the surface being FIG. .S82A. FIG. 5S0. FK^. s8r. FIG. >S2B. coated with very fine washed emery. In Fig. 383 is shown a form of lap well suited to the finishing of cylindrical surfaces. The body of the lap is of cast iron with lead or copper strips a a a a extending through it. 1 hese soft strips serve to hold the emery better than a harder material. By slightly reducing the diameter oi tlie lap by means of the thumb screw, as the grind- ing proceeds, the work may be brought to the required size. In its use, the work is usually rotated at a comparatively high speed, and tlie lap held by the hand. P»y moving it slowly from end to end of the surface being finished, parallel work can be obtained. IIARDKNING AND TEMPERING. 443 oil, immediately after taking it from the fire. This sudden cool- ing of the steel is necessary, and the success of tempering depends very largely upon the manner in which it is done. The shape and character of the work must in every case determine the manner in which the steel is presented to the cooling bath. Salt added to the water in which the quenching is performed intensifies the hardening effect. If the body of steel is large, a large volume of cooling solution is necessary. When the work is of a bulky character, that part which first enters the cooling bath is quite apt to harden better than the top. inasmuch as the boiling action prevents the water from coming in actual contact with the surface longer at the upper parts of the '■ work than at the lower. For this reason, on heavy work, a large jet of water is frequently forced against the upper portion of the work. Cooling in oil is for many classes of work considered superior to water or brine. In its softer action and more rapid conduction of the heat from the steel, lie the advantages in oil quenching. Sperm or cottonseed oils are those usually employed. In using the fish oils, some means of ventilating that will carry away the disagreeable odor should be employed. Springs of all classes are usually hardened in oil. When the lead bath is used for heating more or less of the lead and its dross will adhere to the work if it is put in dry. By covering the work with a thin coating of soft soap before im- mersing it, a thin charred covering will form over the surface of the steel which prevents the lead from adhering to it when re- moved from the bath. By first plunging the work into a brine solution this coating is removed, leaving a clear gray surface on the work. When the workman is not familiar with the hardening of a particular brand of steel from which some expensive tool is made, it is usually advisable for him to experiment upon a small piece from the same bar and thus determine the lowest heat at which the steel will properly harden. It is important that the article hardens on the first heat as reheating is quite apt to injure the quality of the steel and adds to the possibility of loss by cracking. Having hardened the work to a degree considerably beyond that required, it is then necessary to temper it, which involves the reduction of the hardness to the point necessary for the work regmred of the tool. The tempering of steel is accomplished by 444 MODERN MACHINE SHOP TOOLS. graary to cover the oil closely, as O "^tJ the liij^li temperatures em])loyed. »f the vessel and the temperature o properly haatdr itire^MM||M le t^^^H HARDENING AND TEMPERING. . 445 gradually raised until, in the present example, the thermometer indicates a temperature of 500 degrees. In order to obtain a perfectly even temperature in the oil it is advisable to arrange for some means of stirring it while the heat is being applied. The basket and its contents are taken out when this point is reached and immersed in cold water with the assurance that a uniform temper has been obtained in the entire batch. In tempering by color, the article after being hardened is made bright by grinding or buffing. Taps and reamers for example are. after hardening and before tempering, ground in the flutes, thus leaving bright surfaces to show the run of the color. The article is then held over the fire, being constantly turned in such a manner that all parts are equally exposed to the heat. The raising of the temperature should be gradual and the surface closely watched for the first show of color. The color will start with a very light tinge of yellow which gradually changes into a straw yellow and next into the brownish yellow. If it is a tap or a reamer it is quickly immersed in cold water just as the yellow blends into the brown. If it was, for example, a cold chisel, the colors would be allowed to run from the yellow through the purples and into the dark blue. As is the case when heating for hardening, difficult work, especially if long, can usually be heated for tempering in a muffler to very good advantage. An excellent method of heating for tempering small tools, as taps, reamers, cutters, etc., is in a bath of sand. A suitable tray covered with about one inch of pure white sand supported over a series of gas burners is employed. By first burning all the im- purities out of the sand false colors will not be shown on the Articles being tempered. The article, if small or thin, can be laid on ihe top of the sand, but if larger, it should be buried in a small part of the surface being exposed to show the of the color. pering of n piece of steel, the strains are such that article usually undergoes a change. This may ^fjardening or the tempering or both. In such ters and reamers which receive their final after they are tempered slight changes in ►me. With long taps, drills, formed cut- more serious question. Take, for ex- ) feet long. Although the greatest care 44^> • MODERN MACHINE SHOP TOOLS. is exercised in tempering, it usually comes out badly bent. In straightening work of this kind it is necessary to heat it very nearly to its temper point, place it between a pair of centers, revolve it quickly by drawing the hand over it and note with a piece of chalk the high point or belly. Place it with the belly down and by means of a lever or small jack having a quick pitch screw, spring the work in the direction opposite to its curvature and beyond its proper position an amount somewhat greater than its temper bend. Hold it in this strained position for a few seconds, remove quickly and immerse in cold water. The ex- perience gained in a few trials will usually enable the operator to successfully straighten work of this character. As a general rule it is not advisable to leave tool steel long in the fire as *'soaking'' is usually injurious to its structure. Oc- casionally, however, a piece of steel known to be of good quality will resist hardening properly when treated by the regular meth- ods. In such cases it can usually be hardened if allowed to re- main in an even fire and "soak" for a considerable length of time. When a hard surface and soft center are required, as is often the case when- the tool must stand severe strains and shocks, it is given a quick surface heat, the core remaining comparatively cool, and then plunged into the cooling solution. This hardens the surface and leaves a soft strong core. Large mandrels. l)unches. dies and articles of that class are usually hardened in this manner. As the high carbon steels harden at comparatively low heat^ they should never be ^iven a high heat either for forging or hard- ening as the dangers of burning them are great. I'^orged articles, as lathe tools and cold chisels, are usually hardened and tempered with the same heat. In such cases only a small portion at the cutting edge is tempered. It is heated for a considerable distance back from the part to be tempered and the heat in this portion is used in drawing to temper the cutting portion. For exain])le, a cold chisel which should be tem- j)ered for only a short distance back from the point, is given a proper heat for hardening at the point and this heat allowed to run back two or three inches. In quenching only the point for a half inch or so back is immersed and held until the red has nearly faded out of the heated portion. It is then removed and the bit brightened up, by a few quick strokes over its surface with a piece of emery cloth, sand stone or any grinding material at HARDENING AND TEMPERING. 447 hand. The operator then watches for the color, the heat in the balance of the tool being sufficient to draw the point. The straw colors will start first and move toward the point; these will be quickly followed by the purples and the blue, and just as the required color reaches the point the tool is plunged in the water. When too much heat remains in the tool after the hardening of the point, the temper draws too fast and the point must be im- mersed a second time to check the drawing, as it would not do to immerse the whole tool while so much heat remains in it. On the other hand if too little heat remains with which to draw the temper, it will be necessary to draw in the open fire as above explained. What are known as tungsten or self-hardening steels have come into very general use for machine shop cutting tools which require no machine work upon them and little or no forging. These steels are produced by adding several per cent of the metal tungsten to the carbon steel. This makes a steel possess- ing great hardness without the necessity of tempering. It is very "short" when heated and requires great care and skill in forging. It is usually used in special holders and ground to shape without the necessity of forging. After heating for forg- ing the steel must be allowed to cool in the air as immersion in water is sure to crack it. It must be nicked on an emery wheel and broken to required lengths, as it cannot be cut when cold. The demand for high cutting speeds and the comparatively recent introduction of high speed cutting steels to meet this re- quirement is creating a vast amount of interest. These steels are, unlike tungsten steel, capable of annealing and consequently can be used for making tools of finer class, as milling cutters, reamers, etc. In some recent experiments by the author with *'Novo" air-hardening steel, cutting speeds as high as no feet per minute at coarse feed and moderate cuts on mild steel forging without lubrication, were successfully maintained. Although the cutting edge quickly drew to a dark blue it held its keenness for an unusual length of time. It is quite evident that for heavy roughing work these steels are remarkably well adapted and that the rigidity and ordinary spindle speeds of standard engine lathes are not sufficient for its most effective use. In forging the "Novo" steel it is at all temperatures other •ttc heat "hot short" and crumbles or crushes away. It ^mt and for forging and hardening must be given 448 MODERN MACHIXK SHOP TCXILS. a uniform white \vclc had, but because the hr^t \h)(\\ of steel conducts away the heat caused by the cuttinjj much more rapidly than can a small tool. The case hardening of iron and mild steel is a proces<^ where- by the surface of the work is converted into tool steel and liari- ened. This is accomplished by heating the work in oiua:: with a material, rich in carl)on, which gives up its carl^m t*- i::c work. When large numbers of pieces are to fx.* case hanlent-'l the are packed in an in»n box with granulated rawU>ne and nnr charcoal mixed in about e(jual proportions. For the raxN^'rir may be substituted bone black, charred leather or some one <>i the vari(jus special j)reparations for this work. The box is >caki' with an iron cover and lire clay at the joints to exclude the air and prevent the escape of the gases as far as possible. It is tlien placed in the furnace and allowed to slowly heat up to a l<»\v n! Iu*at, at which temjuTature it i> maintained for a length of linif (l('j)en(ling uj)on the (lej)tli it is desired to convert the surface ••! tlic work into t(M)I stcrl. ruder favorable conditions the be treated, they may he Ixatcd in an open tire to a bright red: the siirfaces to* be hard- ened ilien covered with cyanide of |)otassiiitn and again heated before c«)oling in the water. The thickness of the case hardetuM vnrface tliiis obtaitied is (piite thin, liy several applications of tile c\anide it can be made siifticiently th'*'*' ^or most recpiire- ments. HARDENING AND TEMPERING. 449 Another and very satisfactory method is to melt in a black lead crucible, equal parts of cyanide of potassium and fine salt. Bring this up to a bright red heat and immerse the articles to be hardened in it, leaving for a length of time depending on the de- gree of hardness required. Five to ten minutes will give a thick- ness sufficient for all ordinary requirements. When finely mottled surfaces are desired, the work should be polished and thoroughly cleaned before treating. The blowing of air through the cooling water at the time the work is cooled will add much to the beauty of the markings on its surface. CHAPTER XXX. FASTESJSGS. The term "fastening" applies to those deinces ii5*rc b} ^ machinist fur holding together in their relative |x«D.in? rt various elements that make up a machine. Tlieir impcnanrt e mechanical work cannot be overestimated, and a brief descnpoja of the more inifiortant cases seems ad\4sable- With few exceptions, all threaded fastenings use the f-'r-ir \' or United States standard form of thread. In Fig. 585 I'l shown the three forms oi machine bolts most used. The ir^-^. facturers of machine IkjUs have adopted the United States starr^ ard form of thread and as a consequence these bolts run rea>"n- ahly close to size, hut a triHe small. A '^j< boh, for example. \*ill pas> throuj^h a •;« drilled hole. The square head and nut bolt as sJHiwn at A is most used on general work. When the nut comes in a place where it is difficult to get at it wth a wrench, the hexagon nut is suhstituted for the square. At B the bolt has l)oth hexagon head and nut. presenting a more finished appear- ance. The snap or round head machine bolt is shown at C. It ♦ lifUrs from the others only in its form of head. Carriage l)olts arc similar as to diameter and form of thread to the machine ho\{ slmwji at (" with the exce|)tion of a square under the head which ])i(V(iit?* them from turning when used in wood. The length of tins ^(jiiare section is approximately equal to the diameter of the JH.It. ( )n s(|iiarf and hexagon head machine bolts, the thickness of tlu* head is i.j the diameter of the holt and the thickness of the mit is I'm iIh- diameter. The width of the head and nut be- tween Hats is 1)4 the diameter of the boh in both the hexagon and s(|nare. 'I'he width from angle to angle on the hexagon is iwo times the hr^lt diameter. A table of weights and dimensions <'l" maehine IkjUs is given in Chaj)ter XXXIV. Tnnied machine holts, commonly known as coupling bolts, are mneh used for lK>lding together macliine and engine parts. In sneh rases the\ tU closely in reamed holes. .\lacliiiie bolts with specially formed heads and nuts are fro- <|iu-ntly used. As tliey are not regularly 'n stock by the FASTENINGS. 451 InufacturtTs ami miisi l>e mado up to onlcr, any desired form Bay he had. \\ lien the character i>f the work is such that one of the parts that are heing^ secured together can Uc ta])]>ed, a stud holt or cap crew ma\ be used. In \*ig. 586 at A is shown the standard Jrm of milled smd. The short thread is usually madt; slighily |lrgcr than the long one, as it is intended to fit closely the tapped >Ie in the work. The stud when set exten ustaally ooc-ha:: tit Ixjlt diameter in thickness. The check nul is ufTial];. yiz x the outside ; a better distribution of the strainf., however. ^ c- tained when the thin nut is placed on the inside. This xms^i nient of nuts while not alisolutely proof against ih«r wcTicnj hK)se. can usually be relied upon. By alloiii"ing: the boh : «- tend throu|:jh the nut an amount sufficient to permit dr'Uin^ a hole and in»iertinp^ a cotter key, as shown at B, a most satisfic- tory safep^uard ajj^ainst loosinjj the nut is obtained. The o:c€T key in cr)nncction with the jam nut is perfectly safe. Devices of the character of the one sboDm in Fig. ^ arc i-IC. 5SS. FIG. 589. «Hiasi..nnIly used in connection with standard nuts. More often, however, a special mil liavinj^ a notched rim is used in connectinn with a doj^^ to enj^^aj^e the notches and secured to the Ixxly of tlk \v« 'ik. (ap >erc\vs arc similar to couj)ling bolts without nuts, in \\'^. 3()() are shown ihret* styles; at A, a square head; at B. a hexai^on head, and at C', a form known as a tap Ix^lt which is tlirut onedialf the height of the regidar head. In this figftire are ho ^hown the various forms of points used on set screws. A Ad B. the cupped and ovai points, arc regular patterns. The at point C, the cone point D, and the ])ivot point E are specials, Stu(h, cap, ami set screws are regularly n\ade with lioth the 454 MODERN MACHINE SHOP TOOLS. sharp V and United States standard threads ; unless the latter is specified, orders are always filled with V threads. Square and hexagon nuts may be had either hot or cold press- ed, commonly known as black and bright. The cold pressed nuu are those usually used on machine and engine work. A plain nut, tapped and faced on the work side meets the necessititrs m' any case. It is not. however, when applied to well-finished w.^ in keeping in appearance. It is therefore usual to use what are termed semi-finished, finished or finished and case hardened nuts on good work. A semi-finished nut is faced bottom and top and chamfered on the top. A finished nut has its faces buffed or FIG. 594. ^^round smooth in addition to the facing, and the case hardened nut, as its name in(Hcatcs, is hardened after being finished. Keys and feathers are much used in machine construction in the fastening of the |)arts to shafts. In h'ig. 594 are shown the three form^ of keys most used. The round key, shown at A. is used in ])laces wliere little ])o\ver is to he transmitted and ou light work only. A small hole drilled half in the huh and halt in the shaft rectnves the round key. which is usually not tapered and driven firmly in. I)y taj)ping the hole, a headless screw can he substituted for the round key. This not only provides a means for removing if necessary, hut i)revents the possibility of any FASTENINGS. 455 motion in the direction of the shaft's length. Keys of this kind can be properly applied only when the end of the shaft and hub are in the same plane. When the hub and shaft are of different materials, as is usually the case, difficulty is experienced in mak- ing the drill follow the joint, as it will tend to crowd toward the softer metal. Where the strains transmitted are moderate, the flat key shown at B may be employed. As the flat on the shaft can, if necessary, be filed, this forms a most convenient method ot key- ing after a shaft is in place. The width of the key should be from one-quarter to one-third the diameter of the shaft. If the key way is tapered in the hub the key should have the same taper and can be driven firmly to its seat. If the key way is straight it is necessary to Use two set screws over the key. The flat key sunk in the shaft, as shown at C, is the most reliable and consequently most used. It is a tapered key fitting closely in the sides and driven to a tight top and bottom fit. By using a straight key way with set screws over each end the key may be made straight. Practice as to the taper and dimensions of keys is somewhat at variance. Good practice, however, indicates the use of 3-16 of an inch taper per foot with a width of key equal to one-quarter the shaft diameter and a thickness equal to one-sixth the shaft diameter. For shafting a width equal to one-quarter the diameter and a thickness 1-16 of an inch less than the width is much used. Tapered keys are little used by machine tool builders owing to their tendency to throw the parts out of true, due to the radial strain. For such work straight square keys fitting neatly on the sides but loose top and bottom are much used. Straight keys should be set one-half their thickness in the shaft and the depth of key seat should be measured from the sides, not the center, With tapered keys the depth of key way in shaft should be one- half the thickness of the key at its middle section. A recom- mended practice is that the depth of key way in shaft should equal tw'o-fifths the thickness of the key at its thick end. Feather keys are much used by machine tool builders. They are usually of a thickness greater than their wndth and are not fitted tight top and bottom. When fitted in this manner the key docs not hold against motion along the shaft, consequently very close fits between shaft and bore are necessary. Sliding feathers are those which are doweled in the hub 456 MOIiP.UN MArillNB SIlOU TOOLS. where a sliding fit of the spindle through the hub i% required, j with drilling machine spindles, feed rods. etc. Feathers of tin kind should be long in order to resist wear, and as they tJiust ftl the spline in the spindle freely they drive from the httb seat md* shonld therefore have a close deep bearing in this seat If i^ usual to make sliding feathers of a thickness equal to one am! I' If- 595- onc*half the width with one-half their thickness in the noli \\ hen necessary it is of course piissible to reverse the conditiMni and dowel the feather in the shaft, the hub shding over it. The Woodrnff system of keying, as largely used by machine trx>l builders, is illustrated in Figs. 595 and 596. The key U a1 seini-circular disc of soft steel of the required thickness. The FIG. 596. cutter for making the seats is shown in Fig. 488. It is dropped the proper depth in the shaft to receive the key as shown* When a long key is rei|nired two or more of the keys are placed end to end, as shown in Fig. 595. When usetl as a tapered key. as shown in Mg. 596, they adapt themselves perfectly to the taper FASTENINGS. 457 the hub and thus overcome the danger of cocking the work as Sth the flat tapered key when tlie tapers do not exactly corres- >nd. When taper keys are used in places where there is a possibility liaving to remove tliem some provision must be made for either rawing or drifting them. If the key way is sufficiemly long fid the back end of the hub can be gotten at the key can be drifted at, otherwise some form of head must be provided on the key make it possible to draw it. In Fig. 597 is shown ihi- Morton gib head key and the method I'^iti. 597- of drawing it. The under cut head gives the end of the pinch bar a hold and prevents its shpping off. The stepped fulcrum blocks shiiwn insure a square ]>ull on the key. In this manner gib head keys cati be safely drawn. The driving of a wedge be- tween the hult and tlR^ head of the key injures the head and is very apt to bend the key. Tw*^> wedges of Ci^yai angle introduced from opposite sides and driven etpially, answers very well. As they tend, however, in bend the head toward the center of the shaft* a heavy weight should, if the key comes hard, be held under the head. Keys should always be well « »iled he fore driving tliem home 45B MODERN* MACftlKE 5MOr TOOLS, In Fig. 598 is shown a taper pin. They arc made in siisj from Xo. o to No. 10, varying in length from ^ of an inch \oi inches anc! in diameter from apprnximately 5*J2 to ^3*32 ai del large eruL They fit linles reamed with the standard taper intij reamers and are much used by machinery buiklers for sccunn collars, j^ears, couplings, etc. They can 1>c easily r when a^ain put liack it is with the ahsohue certa^ parts are hack in their exact relative positions. They arc however, suited to the transmittinjj of heavy loa*ls» The colter |)in or key. Fig. 599. is but little u^ed for puqw^xs otbiT than those illustrated in Fig. 588, Rivets make the simplest form of fastening. They are. how* ever, permanent fastenings, which can nnlv Ik- rcnuivetl l)y cm FIG, 59a. FIG. 599- tfW FIG, 600. f)fT the bead. Rivets arc httle used for purposes other than thf holding together of metal plates. They are made of soft tuugft steel or iron, steel rivets being most used on the heavier slccf plate work, (jood rivets should stand riveting up cold, withmitj cracking, a method most used on Ught work. For heavy pUte as used in btiiler and structural steel \v<)rk, the rivets are of 1 forms shown in h'ig. (X)0 and are set liot. Riveted joints are of two k^j-V lup and but are shown at A and B. Fig. 6o| lap over each other, while in iht ly against each other and a co^ antl rivetetl to each t'iigt;^. A single riveted jtjint is one i»» *-e used. The lap and bull joint are set hot. rov edires FASTENINGS. 459 »f single-riveted joints. When two lines of rivets are used it »ecomes a double riveted joint and three lines a triple riveted QJnt. A covered la); joint is shown in Fig. (x)2. A cover plate no. ho 2. lI and n%€tcd over the jomX as shown. The lap joint through the cover strip which is also rivetetl to the ' the joinL A double cover butt joint is shown in h the rivets in duuble shear. 460 MOriRltK MACniKR SHOP TOOLSi. Kivct holes are puncheil or drilled. Tlic latter mctknd nl much the more desirable, but owing lo its greater cctsi, is noi««| <'\lensivel\ usetl as puncliing. In llic |>unching of rivet hofej tbe inetal around tbc hole is injuretl by the jiressure erf thfi puncb and as the boles must lie lard out separately to cadi ihecij v/:/// \vNv\m\\\i ""■V^ Yt Fu;. 603. FIG. 604. it is difficidt to make them iriaicb properly, lu ilrilling. bottl^ plates are usual!) drilled together and the metal is not tojl in any way* By punching holes somewhat smaller ih^r nd reaming lliem out» the objection to ptlH FASTENINGS. 461 come. If the plate is thick the edge after punching should be thoroughly annealed. The use of a drift pin in rivet holes to bring them fair is very objectionable as it strains the plate, fre- quently cracking it. In the drilled holes the sharp edges left are objectionable and should be slightly rounded for best results. Rivets are usually set hot as they fill the holes better and due to their contraction in cooling draw the plates very firmly to- gether. In cases where the rivets are long, it is usually necessary to cool the heads before riveting them, as otherwise the excessive amount of contraction is quite apt to break the rivet. It is most important in all cases that the amount of plate lap and the size and pitch of rivets be properly proportioned. The strength of a riveted joint depends largely upon the man- ner in which it is put together. When properly designed and put FIG. 605. together, single-riveted joints will average from 50 to 55 per cent of the plate strength and double riveted joints from 65 to 70 per cent. A stay bolt is a piece of iron or steel threaded its entire length and used to support parallel surfaces in boilers which are com- paratively close together. By means of a long stay bolt tap, the holes in the plates are tapped together, the bolt is then screwed through the plates, cut off and riveted over, as shown in Fig. 604. When the plates are too far apart to permit the use of threaded stay bolts, some other form of stay must be used. The "il stay, Fig. 605, is frequently used. This braces the flat "hell of the boiler. The feet are riveted to end and I connecting them is of the proper size to carry 462 MODFJeX MACfliKE SHOP TOOLS. When ilu* (lianuntT nf the &hdl h greai, the icei arc attachd to both ends, and the lie rods run the entire length of ihe boikr. When a tuimlxT of such sta) s are used in ^ tK>iler they mtist k- d the same length as other wise an excessive strain is thrown tm tlit short ones;. In many cases flat surfaces, as for example, the crown shwt PHfHffi fr^ *tiPti 1 1 FIG. 606. of a fire box, are supported by arch or girder stays. Such a stay is shown in Fig. 606. The ends of the stays are supported on the sides of the fire box and the crown bolts shown support the crown sheet against the downward pressure. CHAPTER XXXI. GEARING. The term gearing, although a general one covering all means of transmitting motion, is more especially applied to wheel gear- ing in which motion is transmitted from one shaft to another by means of toothed wheels. Two perfectly smooth rimmed wheels rolling together consti- tute a geared pair, commonly known as friction gears inasmuch as the one drives the other by friction. When the force trans- mitted is in excess of the frictioned resistance, slipping occurs and consequently a fixed relationship between the axes of the two gears can not be maintained. Such a pair of wheels are shown in Fig. 607, A and B. In general practice frictional gearing is not extensively used. It is frequently found in mill and hoisting work and more especial- ly in gears for reversing purposes. This class of gearing should be very carefully made. The wheels miist be round and the sur- faces as true and smooth as possible. At least one of each pair should have a soft surface as of wood, leather or paper. This should be the driving wheel,- the driven having an iron face, as in the case of any slippage, the wear on the soft-faced driver will be equal at all points on its surface and it will tend to retain its original round condition. If on the other hand the iron faced wheel is the driver and the soft faced wheel for any reason should stop, the driver would quickly wear a concave spot in the soft cover of the driven wheel. If wc assume the wheels of Fig. 607 of the same diameter and rolling tfjgethiT witlnnu any slip, a point on the rim surface of (ine travels :it the same rate of speed as any point on the rim of the other. distancL- that these points travel in the unit of time is cal *i; rar vel ity." The T..i^^^^^^^|is ot bt Tnaintained- If. bawTT«'. i)«5d3 aiit formed x - iurfaofs of the mheeU of sixrh a form liai ib ^fiKr:xs^ ^i^^a&y in tht lactfaod^ practiced by the leading mai FU;. 'Vjry. MO. 6io. lirowTi X' Shnrpc make tlic ^liametcr of the base circle .96^ the |)it
  • 4 the circular pitch. Describe the semi-circle B O. The base circle passes through the point A. The arc B" B' described about A as a center gives the tooth outline approximating very closely to the true "involute." By stepping around the base circle the other tooth curves may be •drawn in. The line X X drawn through the points A and B is called the line of action and is in the Brown & Sharpe system 14}/^ degrees from the normal tangent Y Y. When "involute" gears have less than 30 teeth, the single arc approximation cannot be used inasmuch as the space left is too FIG. 611. narrow at the bottom, causing the face of the' mating gear tooth to interfere. In these cases the arc is carried from the addendum to the base circle. From this point the flank is drawn for a short distance parallel with a radius to the middle of the tooth space and completed with a short arc described from the pitch center of the adjacent tooth and blended into a fillet, the radius of which is equal to 1-6 the width of the space at the addendum circle. By some authorities the single arc approximation is not recommended for tooth outlines of gears having less than 60 teeth. The tooth of the "involute" rack has straight sides, which right angles to the line of action, as shown in Fig. 611. he rack is to gear with pinions \\av\tvg i^>Ne\ >Jcv^tv -jf^ 470 MODERN MACHINE SHOP TOOLS, teeth, it becomes necessary to roittid the addendum of the radr teeth to prevent interference with the flank of tlie ptnioti tocjdk The Grant odontographic method of laying out *invohi^ gear teeth to approximate arcs is given in the foHowttig taJsh and illustrated in Fig* 612, GRANT*S INVOLUTE ODONTOGRAPHY Teeth* iMvidc by Fbct RadfL the Diametral Fitch. Multiply ^y the Circular Mtk !«> FUmk Radius Pmcc RaiJtus. FUnkRMn^ 10 3.38 .69 1 .u It 13 a. 40 3.51 5 .*7 -31 n 3.62 1.09 'S3 '■H U 3.73 1.33 .87 •J9 IS 3.82 1-34 .90 43 16 3.92 1.46 :P .47 \l 3^oa J.5» SO 3 12 1.69 -99 .54 19 20 3-23 3.33 I'M I 03 1.06 :g 3t 341 1.90 K09 :S 22 349 2.06 i*ti n 3'57 * 2,15 1. 13 i -69 24 ^M i.U 1.16 1* as 3-7^ 2*33 I 18 .74 a6 3*72 a.42 L20 77 ^1 3^SS 2.50 L23 So 2S 3^93 2 59 t*2S M 39 399 2.67 I 37 .85 30 4.06 2.76 1 29 .SS 3' 4.13 285 J.3I ■ 9' ^3 4.20 2*93 1 34 .93 33 4.37 -' 3.01 1.3^ .96 34 4-33 3.0Q 3 >6 1,3s •99 3S 4.39 1-39 1.01 36 4,45 323 1.41 LOS 37--40 4 20 I 54 41— 4S 4.63 148 46^51 5.06 1,6[ 52—^ S-74 &.52 185 6t — 70 307 7t^90 7.72 3.46 91—130 9^78 3 It 121—810 13*38 4 36 181^360 31 .63 6.S8 Draw the rack tooth by the special method. In this system all gears up to 37 teeth have tooth outlines 1 a douhle arc approximation and ahove that number a single a: outline. These determinations are based on a 15 degree line < action. GEARING. 471 In the application of the Grant method, Fig. 612, the pitch, addendum, root, working depth and base lines are laid out. The base circle is taken at 1-60 the pitch diameter inside of the pitch circle. If the data is in terms of the diametral pitch, the face and flank radii are taken from the tabulated columns under diam- etral pitch, and if in terms of the circular pitch they are taken from the columns under circular pitch. These values are divided or multiplied, as indicated, by the pitch. The pitch points are next located, and with the dividers set to the face radius, the faces are drawn in from the pitch point to the addendum with centers in the base circle ; and in like manner with the flank radius, the flanks are drawn in from the pitch point to the base line. From the base line to the working depth the flank is a radial line V« F^-*^^^^ f RACK •vV>} 0 tSs^^^' /l>*!»*TV^ / y^ t ^rrcH If TffTH ^^oy FIG. 612. from the center of the blank. A fillet between working depth and root completes the tooth outline. The rack teeth in this system have flanks, and the inner half of the faces, at 15 degrees with the pitch line. The outer half of the tooth face is drawn from a point in the pitch line with a radius equal to 2.10 inches divided by the diametral pitch or .67 inches multiplied by the circular pitch. Gears having the **involute** form of teeth are the only ones that can be run with the axes at varying distances and still trans- mit uniform angular velocity. The line of action varies, how- ever, as the axes are separated. In the "cycloidar^ system of gearing the tooth outline is made of a double curve, the face being an "epicycloid** and the flank xycloid." The system is commonly known as the **epi- * system. 4/2 MODERN MACHINE SHOP TOOLS. An "epicycloid" is the path of a point in the generating circle rolHng on the outside of another circle, which in gearing problems is the pitch circle. A "hypocycloid" is the path of the point gen- erated when the circle is rolled on the inside of the pitch circle. These curves are shown in Fig. 613. When the diameter of the generating circle is equal to the radius of the pitch circle the path of the generating point is a radial line. The prevailing practice makes the flank of the 15 tooth gear in this system radial which for an interchangeable system makes the diameter of the generating circles equal to the pitch radius of a 15 tooth gear. In the Grant system a gear of 12 teeth is taken as the basis. FIG. 613. which gives a stronger pinion tooth for and above fifteen teeth tlian the 15-tooth basis. The rack of the interchangeable cycloidal system has teeth of double curve outline, generated by rolling the generating circle along each side of the pitch line, as shown in Fig. 614. These curves arc cycloids. Although it is a comparatively simple operation to lay out the "cycloidal" form of tooth by means of the rolling generating circle, numerous approximate methods are in use. Notably the (Irant three-point double arc approximation and the Klein method by the use of tabulated co-ordinates, which latter method is also applicable to the "involute" tooth outlines. GEARING. In tlie "cycloidal" form of tooth the line of action is perpcn- ^:ular to the line of centers when the point of contact crosses at line- For all other points of contact the Une of action is at angle witii the line of centers, being a maximum at the points here the teeth make and break contact. In general practice ihe ne of action in eycloidal gears varies from zero degrees at the Tie of centers to about 30 degrees each side of this line. "Cvoloidal" leeth are conjugate only when the centers of the :ears are properly pitched and will not admit of as wide varia- ions in form and adjustment as will the * in volute'* teeth. As e farm of a t(30th in either system changes for every number f teeth, a cutter can be of correct outline for but one number of eth. For ordinary requirements, however, 8 cutters for the FIG. 614. FTG. 615. •involute" and 24 for the "cycloidar* cut all numbers of teeth. in any one pitch from 12 to a rack. The annular or internal gear is a spur gear in which the teeth are on the insiecnme parallel. 474 MODERN MACHINE SHOP TOOLS. As in spur gearing, where we assumed two cylinders as rolling together, we may in bevel gearing assume two cones or portioiu of cones as rolling together. If they roll without slipping, the angular velocity is the same for all points and the velocit)' ntii is the same at any point between the base and the apex. If nov we assume the surfaces of these cones as pitch surfaces, and prc- duce teeth upon them, all lines of which terminate in the apex or focal point, we have a pair of bevel gears which will roll to> ^L fk;. 6i6. j^cthcr without slipping: and will, if the teeth arc of correct fonn, mainiain the same velocity ratio as will the piidi coii<:?»* In i)evel j^ears the relations between pitch diameter, pilrfi and nnnihers of teeth and velocitirs are |l j^earinj^', thns making calculations [)LTtaiiii! same as j^iven for spur jjears. In »)l)taininj^ the data for hevel jL:iars it a secticmal drawinj^ of one-half of each gtt shown the usual method of laying out. The centers ( ) ( 1 and ( ) H a* ' iximum pit and M V are laid out. f Igths pt ^ for ifmr iiit>. OEARING. 475 ^required velocity ratio. The pitch cone lines L 0» M O and F O ' and the Imck cone radii M G and M H are drawn. The calcula* lions for the teeth are based on the largest pilch diameter. Look- • ing^ at the gears from the direction indicated bv tlic arrow ibe ends of the teeth appear as won Id the ends of teeth of spur gears, having i>itch radii equal to the Imek cone radii M G and M H, The outline of the tooth is laid out. as shown, in the same man- ner as for spur gears. The whole diameters X X and the pitch, root and top angle*! are usually measured from carefully made drawings. The teeth of bevel gears may be of the "involute** "cycloidal,'* of **octoitiar' forms an^l can be correctly formed only by a plan- ing process. They may lie cut to approximate form by a rotat- FIG, 6l7* FIG. 6lS. Jng cutter, a method ver>^ largely employed especially on small rs. Bevel gears of the same size connecting shafts at right angles termed miter gears, The efficiency of correctly cut spur and bevel gears is high, from (X* to t>9 per cent, depending upon velocity and (»er- ^s of tiK'tr application. ■ ars are those used in connecting shafts which ' do not intersect. They are but little used, i I lud worm, an example of which is shown nr transmitting motion from one shaft to 1 to it, axes not intersecting- The worm •n?c in spiral gearing, the worm corres- ig but one tooth. 47^> MODERN MACHINE SHOP TCJOLS. The section of the worm as shown at S, Fig. 6i8, isdthl same outline as a rack of corresponding pitch and may be i either the "involute" or "cycloidal" form. The *'involi2tc*'iith I form usually employed, as the straight sides of its tcedi « ^ much easier to produce on the hobbing cutter, Fig. 474, vUi is used in cutting the worm gear, than the ''cycloidal" fonn. As worms are usually cut in the lathe using the regofar change gears, their pitch is expressed in terms of circular piid) rather than diametral. This pitch is usually called the lead of tk worm and is the amount the thread advances at each revolation. The spaces Iwtwcen the teeth of the worm from which the hob is to be made are cut without clearance and the whole diametn ri(;. 619. is made greater than the diameter of the worm by twice the anicmnl of the r(K)t cloarancc necessary. In I'ig. (M[) is shown an end section of worm and worm gear. I'lie \vht)le diameter, tliroal diameter, pitch diameter, and root diameter are in tile same rules as for spur gearing. The diameter of the worm is usually taken at from four to tive times the pilch, but is not limited in diameter, thus making |)<»ssil)Ie ctjiisiderable variation in the pitch centers. As with "involute" gears, the vel|>lication of this class of gearing to elevators and dividing mechanisms. The tooth action h purely a sliditig one anndittg tntcbn,^] whrrr the strains ztr nut ^trat ami the fomi $ho\Mi ^:■■ fkimtectioa lo the teeth agaittst mjur>. The form sh ;. „, hais bm one advantage and that is the passibility of its hmgt m a mtlfing machine without the u^e of a hoh. The teeth ; fkith a spur gear cotter at the angle correspomlmg i^-ith thii of the helix of ilie womt. As this gives a very impcrita. ommi\ between the teeth of gear and worm, h is suited otily to the i mittinis; of ven* Itghi loa«k. WTien the tet'th are 50 iornic4 n \ pm«ihle to vary somewhat the ani^e of the axes from a angie. as for example, if the gear shoim at B was a stxit 1 tile worm would mesh with it by inclimng its axis from its ncm FIG. 611. position an amount equal to the angle of iis helix. This pn duces an objectionable pressure in the direction of tlic gear's ax The distinction between worm and spiral gearing is not clo5C air always passing the line of centers, thus producing a sml'inn]*l In irreat enough to insure 2 pairs of teeth haviiii; ouniact |>««ints constantly passing centers. The wititli ^^i face> will determine largely tl use in an\ v:a>e. wivler faces ant] smaller angles going Since in spiral ^ear> »»n j^arallel axes the spiral a W eijiial. the pitcli of spiral \\i!l Ih» ^.^jual in both gears tliey are "f the sanu Jiiitneter. If, itT example, one gea iime> I lie ]»iicli liianieter -m' tlie •»tluT. in onler to liav -]>iral ant^le its >piral pitdi must W three times as gfrej Willi ilie axes at riirhi anir-cs hotli ijears will have < ..r left hand >pirals. ('on-i*ler a ]>air .»f sj^iral iivar** on j^arallel axes A ai I'i;.:. ^►Ji, willi piir irear when the ;i\:- .•! .^^^45 degree GEARING. 481 axis of B. Continuing to swing A, the spiral angle changes from right to left hand, and at 90 degrees it becomes the same as B. If any other spiral angle, as 20 degrees, had been taken, A would have become a spur gear when its axis had passed through an angle equal to the spiral angle or 20 degrees, and beyond that position the spiral would be left handed, increasing to 70 degrees at the 90-degree axis position. From this the following rules are de- duced : First — When the gears both have right or left hand spirals the sum of the spiral angles equals the angle between axes; second — When the gears are right and left handed, the difference of the spiral angles equals the angle between axes. The velocity ratio of spiral gears cannot be determined by direct comparison of pitch dianfeters, as in spur gearing, but must be found from the angles of the spiral in each gear. Thus if the spiral angles of two gears are the same, the velocity ratio will be inversely as the pitch diameters, but if the spiral angles are not equal, the number of teeth per inch of pitch diameter will vary and the above ratio will not hold. This is well illustrated in a worm and worm wheel, where, if the worm has a single thread, it is really a spiral gear having a single tooth, and the velocity ratio will be the number of teeth in the gear. If the worm has two, three or more teeth, the spiral angle will be different in each case and the velocity ratio equal to the number of teeth in the gear divided by the number of teeth in the worm. Increasing or decreasing the pitch diameter of the worm will change the spiral angle of the teeth in gear and worm, but will not affect the velocity ratio. In any case the velocity ratio will depend upon the number of teeth and their spiral angle, as ex- pressed in the following proportion : v, the velocity of the small gear, is to V, the velocity of the large gear, as D, the pitch dia- meter of the larger, times the cosine of its spiral angle is to d, the pitch diameter of the smaller, times the cosine of its spiral angle. With the axes at any angle the teeth slide upon each other, this action being the greatest when the axes are at right angles with each other. As this sliding contact produces friction between the teeth and excessive end thrust along the axes, spiral gears with axes other than parallel or nearly so are not suitable for transmitting heavy powers at high velocities, as the wear is ex- cessive and the frictional losses make the efficiency low. When the axes are at right angles as in the spiral worm gear and worm, the conditions are the most unfavorable for the economic trans- MACniKE SMOI* TOOLS, fallin; 1 I mission of power, the cfficiencv freqtientlv cent. In all spiral j^^canng an uul thrii>t along U ductd by the ubiique action of the tccfh. This neutralized by placing geam of opposite spirals an the { a* shown in Fig. 624 at A, Before laying out spiral gearing the designer consult the shop facilities for cutting ihem* .^tnc character will usually enable htm tfi adapt ihejn tc stock, and only in unusual ciist> will he 6n*l it ne other than standard cutters. Il will tisiaaJly be found sau&iactofj to deter FIC. 624. rioi propofftioRs from the niles for spur gearing. are of large dtameter, the arms mttst be made 10 resist the pressure in the dirrrtioa of the axb 1 action at the teeth. As the pressure befweeti te^ is co« very small surface, the sirain on the tooth is more sevei the spur gearing, and the oonseqnent wear due to bid greater. In considering spinu ge^ing the First — The fsosmon of parallel or at an angle wtA cadi other: second — tfieM twecn centers, whether at a faced 0 tncl GEARING. 483 "Variation in the distance; third — the velocity ratio; and fourth — the power to be transmitted. When the distance between centers is fixed, it will often be found difficult to obtain correct velocity ratios, as the normal ■circular pitch will usually give a fractional diametral pitch which Avould, unless approximately close to some standard pitch, require -a special cutter. When the distance between centers can be varied, as is usually the case, the proper numbers of teeth, with their spiral angles, to give the desired velocity ratio, may be selected, and the correct normal circular pitch to suit a standard cutter as- sumed. The circular pitch then equals the normal circular pitch e obtained from the expression used by the Brown k Sharpe Manufacturing Company, where T, the number of teeth stampe2. . In I'ig. ()24 at !» is shown a pair of spiral gears on parallel axes, in which the velocity ratio is one and one-half. From con- siderations for strength these gears should have teeth cut with a 10- 1*, cutter. Assinne : Spiral angle, 25 degrees. Xiiniher of teeth in pinion, 24. Xumher of teeth in gear. 36. Xornial circular pitch, .314. Xnrnial R0BLEM 3. — AXES AT RIGHT ANGLES. case of spiral gears with axes at right angles. In this case the velocity ratio will be pro- 486 MODERX SfACHIKE SHOP TOOf^ IKirtional to the pitch diameters only when the spind ang^^ inch. cos (ki (leyfrcos ^Z:^ GEARING. 487 ^ Pitch circumference = .786 inch X 12 = 9.432 inches. 9432 Pitch diameter = = 3 inches 3.1416 2r^ 2 inches \\ iioie diameter — 3 inches -| = 3.25 inches. 8 12 Number of cutter = = 30, giving cutter cos* 60 degrees No. 4. 9432 Pitch of spiral = = 5.44 inches. tan 60 degrees 4.18 + 3 . Distance between centers = = 3.59 inches. On account of the great obliquity of the teeth the pinion should be the driver, and in general the gear having the larger spiral angle should be the driver. PROBLEM 4. — AXES OBLIQUE. Taking up next the case where the axes are neither parallel nor at right angles. Assume the following data : Velocity ratio, i. to 2%, Normal diametral pitch, 10. Number of teeth in pinion, 16. Number of teeth in gear, 36. Angle between axes, 50 degrees. If the end thrust is to be equally divided between the bear- ings of the two gears, then the spiral angle of each gear should be one-half the angle between axes, or for the above problem 25 degrees; and both gears will have right or left-hand spirals. If, however, the minimum amount of sliding between teeth is 488 MODERN MACHINE SHOP TOOLS. desired, then the graphical method ^ven by MacCord miv used. It may be sUted thus : The angle between the axis each gear and the diagonal of the parallelogram having for ; jacent sides lines in the axis and corresponding in length the velocity of each gear. Fig. 625 gives the approximate spl FIG. 625. anj;j:lMI»ION MACHINERY. The tran*nii^>i«»n '•! ]i« wcr h\ fieltin^ is a subject of jjrtat iin]»i»rtaiKV an*! •'Ik* that >hiiiiUl receive more thought aiv! -rj'iy '11 ilu- \thn *i tin- inachini>!. A better knowIe; ami the problems uf Ijell j^eariric incrcar^ei niati-Tially the rv i.r the p:ir]Mi>c •.! transmitting nioti^ni irom the '.'ne to the oihcr. \- it* 'Irive MtiKiTi* ••" it!* irictional re'ii?tance to >lippinjj anl as it i* fi a nv Tf '.r le*- elastic nature, it cannot Ix? tIejK-n'Je*l jp^n f-r ihi iraiisn:i--i«'ii • i exact vel<*city ratio>. 'I !u-rv are iw*- ;:<.neral classes oi belting, tlat an*l p .11 ml. the :• iiiuT iK-inj^ ii>r'l ••!! riat *»r cr«»\vnen jCT'»''Vr! • r -luave piillev-. The materials iise exten>:ve:} i>r;'l -n r t!' !^ lielt- i« '- inrrt .i-inLT the 'irivinj;: |H»\ver anf tin- :x]h'\c material- leather i- tlu- ni'-! i:r.- : r*.;:.* ::V: : \hv ■ i-r :r.- -T --li: :u manufacturing works. !^ ::*;.• r '"l-ii.^ > :r.;i!t in v:iri'»u> jLjrailes. and there :- pr"!- .." • '• ■ r ::..:•' r-;i:. !:l-r:i;i!:r,i^' ••!!> ixce]»te«l. with which the :.;;•:;: :r- : rv.- - :i- i'.ina't ih.at requires lietter iu«itjmi-in in > -«■'•. : . i ■:• .ir'!*:! -• !». tiu;^ "f th.e hi. the ]>r«»per laii- • ■ ^ ..: . — ' :: ^^ ;•.:.': al. w all tlu- jjart rif the hide ust'! in riie • "• ■ ^ :.' : . ::;. ar'- •:-'•'. :r ::- manufacture, are the imfi-'nin: ■'•-".:'• •...-:: ^ *' a - • -! ]»i»vc- >.i leather heltinj;. • ; \. 'J' - -' .-. :; ;i -.:• iliu-iratinj: the character «''f \hc '. .'' • >■ : r ' •!*:: L. 'T.a* ;■■ ri:«n included in the dotted linn- '. ■' - ■'. ' r ■":.' -. ;iT'' > ;^rade- (»f luL-lt. and is termt-l .'. • :*: : I ':> :.i !«■ '■•.:T--ide of the "'Iriitt" is soft anil .'•/ •'.:'!. :':■■ . :• : *". >«''; in oheaji helts. is totally unfit :" • ■ — -: . ; r-i : i : 'i II i< known as the center : > •: a* : .;-: >■ \ 'h.'- :vak:ntr "f the Inrtter belts. Of ■'•:■■•• ^- .-: ! r:: I: i" U is the best, as it is die ^:r :;.-.^- :■.:'. -.■ < -v.:- rw. -art f' Hdc. T BELTING AND TRANSMISSION MACHINERY. 491 J M P K is known as shoulder stock and used for the lower - prades of belting. What is known as strictly short lap, center stock belt, must be cut from the portion A B C D. As there is so small a piece of this grade of leather in each hide it goes without question that much of the so-called center stock comes from the 'parts E F B A and D C G H, with tendency to run into • the portion J M P K. The shoulder stock is tough and heavy, but stretches in an irregular manner and should not be found in first-class belting. Shoulder stock is preferably cut crosswise of the hide, as it stretches into better shape when so cut. All hides used for belting leather should be carefully tanned. FIG. 626. and afterwards curried or softened by "stuffing" with hot grease, a process which lubricates the fibers of the leather and converts the hard, dry hide, as left by tanning, into a strong, pliable leather. The hide is then thoroughly stretched and cut to re- quired widths. As all strips other than the one having the center of the hide as its center will stretch more on the one edge than the other, it is desirable to take out most of this stretch before the belt is put into use. It is not, however, advisable to take out all ol the stretch, as the belt is then rendered "dead," and lacks '^'tidty so desirable in a good belt. ither is scarfed to uniform thickness and by careful 'X>lishing is brought into the smooth uniform condi- found in the commercial leather belting. The 492 MODERN MACHINE SHOP TOOLS. weight of the belt is an important feature, a heavy belt being, as a rule, more desirable than a light one. Heavy single belts are cut from selected hides with a view to obtaining weight. Belts from lighter hides are frequently made heavy by excessive stuffing. This is not desirable. When belts are required heavier than the thickest hides will make, it is necessary to glue two or more thick- nesses together, making **double,'' "triple," or "quadruple" ply belting. What is termed a "light double'* belt is made of two tJiick- nesses of thin hides, one side unusually being belly or shoulder stock. The weight of the "light double'* belt is about one and one half the weight of single belt. Double belt is twice the weight of single; triple three times the weight, etc. In the making of double belts the strips should be so placed that edges of greatest stretch will come opposite so as to average up the stretch and make good running belts. The opportunity for fraud in the making of leather belting and especially in the heavy plies is great. Low prices usually mean light weight or poor quality, which is generally not discovered until the belt begins to go to pieces after short service. Light and heavy double belts are used for transmitting heavier power than the single belt will satisfactorily stand. Usually for drive belts it is better to use a double belt than a single one of greater width. Light double belts are well adapted to use as shifting belts, where there is considerable wear on their edges, also for shifting belts on cones. A double belt should not l)e used on pulleys of too small diameters, as the short bend breaks the joint. In a piece of belting leather the strongest section is on the flesh side. The hair side is relatively weak, hard, and liable to crack. For this reason the hair side of the belt should always be run next to the pulley, as it brings the fibers on the flesh side, w^hich can best resist the strain, under tension as the belt passes over the pulley, and the hair side, which can least resist the strain, under compression. P>elts run in this manner seldom crack, while on the other hand if run flesh side to the pulley transverse cracks arc sure to show up on the hair side which gradually grow deeper and eventually ruin the belt. The hair side of the belt is the smoother, comes in better contact with the surface of the pulley and by actual test will transmit about 25 per cent more power, other conditions being equal, than when the flesh side is run next to the pulley. BELTING AND TRANSMISSION MACHINERY. 493 The ultimate tensile strength of leather belting, depending on its quality, varies through a wide range. Most samples fall Mrithin the limits of 2,000 to 5.000 pounds per square inch, with l,ocxD to 2,000 pounds at properly laced joints. Cotton belting has greater strength than leather, and when coated with rubber clings to the pulley more closely than leather. It is much better than leather for use in damp places or where subjected to material changes in temperature. Leather belting cannot be used in places "where there is dampness, as it starts the glued joints and other- w^ise injures the belt. By a special waterproof treatment leather belting is made to stand a limited amount of dampness, but rub- ber-covered cotton will be found preferable under such con- ditions. Leather belting should not be used in temperatures higher than lib degrees. The power that can be transmitted by a belt varies, according to conditions, through very wide limits, consequently fixed rules cannot be laid down for the calculation of belt powers. As a pull of 33,000 pounds through a space of one foot in one minute repre- sents one horse power of work, a pull of 33 pounds through a space of 1,000 feet in one minute would represent the same amount of work. By increasing the velocity or the tension, the work performed is correspondingly increased. The working strain on good leather belting may be taken at from 45 to 60 pounds per inch of width for single belts and at double that amount for double belts when the thickness is double that of the single belt. From the above, a heavy single belt running at 1,000 feet per minute will transmit 60-33 o^ ^-^ horse power, while a heavy double would transmit 3.6 horse power. At 4,000 feet per minute these same belts would transmit 7.2 and 14.4 horse power respectively, and if the widths were in- creased to 10 inches they would transmit 72 and 144 horse power respectively. The tables ordinarily used give powers somewhat under the above, a common rule being to allow one inch of width at 1,000 feet per minute for every horse power with single belts and one-half inch of width for double belts. This rule gives a most liberal margin, especially for single belts. Excessively tight belts should be avoided not only because of the injury to *fte belt but because of the excessive strains on shafting, boxes, oulleys. Covering the face of the pulley with leather increases liesion of the belt from 30 to 40 per cent. A cover of this 'St be carefully put on, for best results, the leather from 494 Mopnii MAcnixK soor tocn^ wltich ft it made being fcarf ed lo uml€prm thickiicss and loij dotdy over ihc pulley. Wlieficver the dtii racier of the work pcrrmis, leather kdli lid be made efidJeftii by beveltftg the ends and making i ^\aA ap joint. I1iis makes a strong jmni that runs smoothly aver ihr | '"pulleys, and is most important in the case of high speed fcdb i)fK*rattng on pulleys of small diameters. In dcruble Wu the joint should be lapped as shown in Fig. 627. It is not ncci: %ary u> 3. FIG4 617. use rivetn or other fastencrii in connection with the gbed bp' joints. In fact, the best practice now disfienses with than €»- tirely. In glinng the joint a special bch glue should be used and applied hot to both surfaces in order that it may penetrate Hcll into the pores of the leather. The surfaces must lie damped firmlv and squarely tnjc^etlier and given sufficient time to drr well/ The lacing of belts is u ntatier of mucii mi|>vu*iii*.<; and suf- rro, 62$, k ficient care is not ordhitirily exercised in this work. The ttfi li<»tiorcd nielhod of lacing belts with thongs of rawhide has nearly given over to the l)etter practice of using wire lacing, or a limited fi'w i>i the many patented belt fasteners. The usual troubles with 1 fasteners arise not from the fastener itself, Init from its improper application, For any kind of fastener tlic belt must be cut square, , a try s(|uarc and not the eye being ih ^ for this work. The ends must be held squarely lojt:' ;lir fa^itcning is^ made. riKLTlNG AND TRAKSMISSIUK M \( UJNHRV. 4i>5 Heavy belts should, for gluing or lacing, be drawn together by Tlieans of the belt clamps shown in Fip^. 628 in place on the pulley!5> ; ^s I he edge of a wide, tight belt is invariably stretched when Txtn onto the pulleys. On the side next to the pulley the lace leailicr, wire, or fastener shonld run parallel with the bell's length » •^iid not cross each other, as in tl^at case they make a rough PULLEY SIDE ^ULLEV StOE PIG. 629. FIG. 650. iiiriface and wear off very quickly. The holes should be punched cactly opposite each other and should be the smallest possible that will let the lacing through. In the case of raw hide lacing, the usual mistake of using too few strands and too heavy a thong should be avoided. A satisfactory method is shown in Fig. 629. tie strands on the inner side should be about 5-8 of an inch apart, the staggering of the holes gives a firm hold on the ends of A9* MODERN MACHINE SHOP TOOLS. the belt. It is best to lace from the edges to the center, tj-iag < at the center. In Fig. 630 is shown the method o? iaciiig belts wilb wst lacing. The method is practically ilie <*amc as with thongs. TV wire used is of comparatively high tensile strength anti pliable. By cutting shallow grooves between the hole* ♦ pwHcy side of the belt for the strands of wire to lie in a sm«x)th and durable joint is made by this means. The ends sfaoukl be carefully tied off or otherwise there is dan|:er of injuring tbe hand in shifting the belt. Leather link belts* an example of which is shown in 1%. 631, are used to quite an extent for certain classes of work, Tlir hiiilt ujj of leather links hinged together by rods, as shown n figure. They are very heavy, run smoothly, transmit heavy 1^«4 no. 651 B per inch of their wii times the width of the belt. The centers must be reasonably far apart to give good results. When shafts are in the same plane and at an angle with each other they may be connected as shown in Fig. 639 by what is called a quarter-twist belt operating over mule pulleys. The pul- leys should all be of the same size and well crowned. By having 500 MODERN MACHINE SHOP TOOLS. the mule pulleys so mounted that their axes may be inclii each other, the driving pulley may be made of a larger oi diameter than the driven. When belts run on straight-faced pulleys it is nea guide them on the pulleys in some manner, as otherwise quite apt to run off, and especially so if the shafts are no parallel with each other. In such cases a pair of fingers, which the belt runs, is placed a short distance from th pulley on the side of the belt which leads onto the pulley. on the edges of the pulley are frequently employed. As t \'U,. 639. torm of llanpfo guides the l>cli after it makes its bearing face of the ])iillev, the destructive action of the flange on 1 of the heh is great, due to the resistance of the belt to a in direetion after it has come in contact with the pullc> This action is re(hiced somewhat by under cutting the the tiange so that only its outer ])ortion comes in contact > edge of the heh, thus virtually forming a guide at some > from where the helt comes in contact with the pulley's face When helts arc not to he shifted the usual method of is hy crowning the face of the pulleys. The lielt then tend: BELTING AND TRANSMISSION MACHINERY. 501 "-^ the high part of the pulley for the following reasons: If, as ODwn in Fig. 640, the belt is forced to one side, the edge a be- omes stretched, making that part of the belt in contact with the ^^nuUey's surface of conical shape, with the edge a traveling faster ^lan the edge b, thus causing it to run in the direction of the -"^sitfTow and to center itself on the pulley. When the shafts are parallel a belt always runs to the high -|>art of the pulley. If, however, the shafts are not parallel and the liigh side is caused by the position, and not the shape of the \i. FIG. 640. FIG. 641. pulley, as shown in Fig. 641, the belt runs to the low edge, inas- much as it passes onto the pulley in a spiral direction and all points when they first come in contact with the pulley's surface are carried in the direction of the pulley's rotation as indicated by the arrow. When the distance between shafts becomes great, leather belt- ing is no longer suitable for transmitting the power and con- necting shafts or rope belting is substituted. The connecting shaft method is but little used and is well adapted only when the shafts 50J MUDKRN MAlIIINK SIIOI* nMiI^. arc in the same horizontal plane, tlic o»nnoctitjn usually Ijcin^ nia«lc by two (juartcr-iwist Ix^lts as shown in Kij^. 039. I'hc iiso of ropo transmission has nearly superseded the niiu meihiul l)ccause of its hij^her efficiency and jjreater riexilnliiy. u i< difficult to conceive of any combination of shaftinj^ as t'» juni;- tion, anj;:les. etc., thai cannot be successfully connc-ctcd up ijv rope drives. As wire rope transmissions are not frecjiicnily used in >lyn drives, only those cases pertaininjj^ to cotton anc! nianila rojKrdnvei will 1h' considered. i-'or the transmission of i)o\ver. only the best of cotton an»l manila n>pe is suitable. Cotton rope because of its ijreater t1.'\i- biliiy is better adajned for service on small diameter sheaves tiun manila ro\\c. It is not as durable as the nianila. has not the ten- sile streuj^th. is harder to splice, and hijj^her in first cost. The manila rope used for transmission puqioses should \k '»f the lH*>t ]Hi>>ible (|uality, maiuifactured from Knif*" fiber manila which has been carefully cleaned and selected. The smaller r-UK's are made oi three st rani Is, with four and six strands for the heavii-r ro]H*s. rile l'»'ur and six strand ro])es have a central core annuwi which ihe >irands are lai*l. The ])rincipal wear in transmissi«>n 1* pe ci'Tiu'< from the continuous rubbinp^ of the fibers tojjether. To ' \iivt ir.e ibis has been the j::reat study on the \n\n of the traiisiiiis- ^i. n r«^]v nianiifacturer<. The free use of a lubricant, as plumbai^^> ,,:;.! :a'!»w. .n ilu- v'i>re and inner strands of the ro]>e serves t»> >. i\<:\ .iiiil viii'i'.ce ilu- wear on the fiber. 1 lu ^I'lx'i'.ij^ of trar,>:nission rtipe is a most important i)pera- •'.. !' ,1:1. ■ • v.c upon wl:ioli the success of the oiiU in the rope, yet if prMji- <'.'.\ : -..ilv ".: will wear well and seldom j^ives trouble. It is t be so N,,\::./ :'•.:: :l'v\ wi'.'. nnt wear or cause their covering strand> :,' w...- . •'. ::::< fricinv: the t'.ids enouj^h to allow them to whip . ;■: ,> •.'\\ :\i^< .'\c!' :he . t Md sailors do not know hi»\v '..' X- ■ .\ •• .i:'«»!r.i-ry splice. It is extremely dif- [w\\'.\ : -■ !:.e a i^iv\\ * f new r- : i into an old one. as the «-tri'toh ■v y\:\ . •."v- I !.; :. \\\ Abii^'b ca;*-..- it t.» pull away from tlu- lifw. i I'vu ■«» aN^^ i^^'lv;.i^■,■ai^\• diltVi\v.v\- in diameters. In such ca>f^ BELTING AND TRANSMISSION MACHINERY". 503 the new rope should, if possible, be thoroughly stretched before putting it in, and the old rope laid slack in the splice, an amount FIG. 642A. PIG. 6430. FIG. 642B. PIG. 642c. PIG. 642B. wholly dependent upon the judgment of the workman, to the stretch in the new rope. The illustrations in Fig. 642 and the instructicmi 304 M'ifjKKN MAt a: ST. rH* ^ 7 .♦.•-.-. til* 'St fiirni>hc'l l»y ilu- Link licl: Machirjer} •! .cr:ar.. :.-: siaiKJanl pjjk* sjilices. Hi > I'LICK A FOLR-S7R.% ND M A N 1 1- -. 5: r I- Tic pii'ces of twine a and h around the r :pe :■: :"c ?:'-::i half tlu* kiij^ili of ilu' splice in-m the end*. See li'.lr : -r of .sj)licr. ) L'nlay the >iraml> oi each P/pie lack t:- ±x IJiitt nr mesh the roix'> tojjether and iwi^: c«: rrry^idri In^eiher i lenj^th, laying strami 2 in its p'acc. strand 4 one-ed with a small ])iece of twine. Take half strand I enrres|>t)ndinj^ half >tran tlu* same appearance as the rest of the rop< now |>ii«»s (111 t(» I ). I lir i<»pr is now (ipiMiecj hy inserting a marlinspike 1> strand^ S and thr «.ilur two strands at a i)oint just l>eyo kiH'i. Iliilt' strand SI) is pulled out and half strand 7a pul in |»l.hr « t" liall" strand Sh; care being taken in pidling i s! I. II hi ;m i») kerp the rojK* smooth and firm, also to ke \.mi^ iwistrd ilir same amount as in the rest of the rope. •f liniu this nprraiiiin until about one-(|uarter of half strancJ iiM-d. I hen (Iroji a yarn from each strand hy pulling < ImIi -ii.iiid Sb less one yarn and ])ulling in half strand ; oiu \.iiii. thus keepiuji:' the munber of yarns in the strai s.Miir .iiid ibv* voyc the same si/.t- as at any point. Go on as 1 dii-ppniL: a \arn at every sivond opening until all of the yar thoppvd. riu- pped \arns are laid over the strand woikr«I (Ml and pulled undrr the adjacent strands respe< at tlu- imie tbe\ arc dropped by opening the rope. They ar BELTING AND TRANSMISSION MACHINERY. 505 cut off to about 2 inches long. Half strands 8a and yh are treated in like manner, going in the opposite direction. The ends of the yarns left sticking out will partly be drawn into the body of the rope and partly worn off in a short time, so that the locality of the splice can hardly be detected. In the larger ropes from one inch up, two yams may be dropped at a time when that stage of the splice has been reached, ^s it would make too long a splice to drop them one at a time. Size of Rope. Length of Splice. H inch 12 feet Va 13 n 14 I H 1/8 15 IM 1 6 iH i8 1^ iK' i8 iVa 20 There are two systems of rope transmission in common use — the "multiple system" and the *'continuous system." The "multiple system" consists of independent ropes running side by side, while the "continuous system" consists of one rope wound around the pulleys several times. The "multiple system" is much used for transmitting heavy powers, and while not so adaptable to many special drives, possesses some important advantages over the "continuous system." In the case of a rope failure it can be removed, the balance of the ropes carrying the load until the repair can be conveniently made. As idlers and tension pulleys are not ordinarily required, the rope is not sub- jected to a continuous reverse bending, thus making it more dur- able. In Fig. 643 is shown an example of the "multiple system" of rope driving. In the "continuous system," an example of which is shown in Fig. 644. a single rope is used, it being wrapped continuously about the drive and driven sheaves with a tension idler to take up the slack. The use of the tension carriage is necessary in order to take up the stretch in the rope and maintain a uniform tension in it. * The position of the tension carriage should be such that it takes care of the slack at the point where it naturally accumulates. In the example shown the last strand from the driver leads over 506 MODERN MACItlNte StIOt* TXXlLS. an idler sheave mounted at the side of tlic drivcu sheave Tk tension is taken from this sheave hack to the opposite groKit | <>n the driven by nican<» of the tension sheave^ the axi* ui wted is sufficiently inclined to lead the rope proixTly. The applications of the rope drive are inany. and for tbe 1 FIG. 643. smooth, quiet transmission I'l |>Mv\t't it has become a popular niethocL Perfect alignment c»f sheaves is not necessary, and' shafts may be run at any angle with each other and at any dis- tance within reasonable limits. Hit' sheave |>ulley is one in which deep groi>ves are cut in its rim to receive the wraps of the rope. They are made of cast irotj 4 mc 644 with the surfaces of the grooves very carefully polished, as any roughness wears the rope unduly. For driving and driven sheaves the accepted form of groove is the one shown tn Fig. 645 at A. The angle of the sides of the groove at the pitch line a a is 45 degrees with each other. The sides are. however, slightly con- cave in section, which produces a rolling motion in tlic rope re- BELTING AND TRANSMISSION MACHINERY. 507 suiting in a more uniform wear on the rope than when it r\ins without rolling. The width of the groove at the pitch line is such that the rope bears on the sides, thus wedging in and causing a high fric- tional resistance to slipping. When used as an idler the bottom of the groove, as shown at B, is semicircular, the radius being equal to or slightly greater than the radius of the rope when new. When the sheave has two or more grooves it is very important that they be of the same shape, size, and diameter in order to avoid any slipping or "creeping" of the rope. Sheaves smaller in diameter than 30 times the diameter of the rope should not be used with ropes under ij4 inch. With ropes over 1^4 inch in FIG. 645. diameter the sheave should not be less in diameter than 40 times the rope diameter. The larger the sheave the less the bending of the rope and consequent wear upon it. The usual speed at which ropes are operated is between 3,000 and 4,000 feet per minute. When the speed exceeds 4,000 feet, but little gain can be had in the power transmitted up to 5,000 feet, and above that speed the power transmitted, due to the ex- cessive centrifugal action, falls off rapidly. The table in Chapter XXXI\\ compiled by C. W. Hunt, gives the horse power of *'Stevedore" transmission rope at various speeds. Shafting as universally used at the present time for power transmission purposes is of mild steel finished smooth, round and true, either by turning or by cold rolling. Turned steel shafting 5o8 MoDicitx MAciifKE snnr loout ntits in sb^ f*i6 inch uniii*r the coimnon sizc^, ss i l$-f^ 33 1 7-16, rtc. it liavitig hetn finished from black Jtoek of 1.^ mchc*i dian>cicr. respectively* by ' spcdaAi : _ V, The linal mu* Mir face en tun • _ ;* nljUic^t. FtO. ^6. (lasstr^ a hollow reaincr or shafting burr uver ii, ar by a final I ratling procesis. CJoW rolled shafting is given its final finish by Ctilil mUing process which leaves a true smooth surface and alf^ intensifies and sittfens the material. When a nunilK?r of lengths of shafting are to be connected together a suitable coupling nitts^ be employed* A flanged face cotipltng is shown in Fig, 646. These should be fitted to the einb of the shaft and the faces tumciJ tn \ place, thus inMning faces at right angles to the axis of the shaft j and a true connection. Compression couplings are of numerous j forms, many i>osscssing good points* In Fig, 647 is shown BELTING AND TRANSMISSIOK MACHIKERY. 509 nple and effective compression coupling. Tt consists of two ^mictrcular shells fitted and bolted together. The shaft ends -^ome togelher in the center and are held concentrically true. A key properly fitted makes a positive drive and a pin projecting a short way into the shaft at each end of the coupling prevents the shafts from pulling out of the coupling. Shafting lengths should be so selected as to bring the couplings [>se lu the bearings. For example, if bearings are eight feet apart 4-r*r FIG. 648. le shafting lengths should be 8, 16 or 24 feet. When it 5s fre- ■uently desirable to disconnect two lengths of shafting a dental [)upling, Fig. 648. may be employed. The construction is evi- t-nt. The end of one shaft should extend into the opposite feouphng enough to hokl the ends concentric. A bearing shouhl be provided on each side of this form of coupling. They cannot be operated when the shafts are in motion. The universal couijling, Fig. 649, is suitable for connecting FIG. 649. shafts which are at a small angle with each other. They will oper- |le at an angle of 25 degrees, but are not well suited to the pur- )se when the angle exceeds 10 or 15 degrees. Pulleys for power transmission purposes are of two classes, j^hole aifd split. The whole pulley is made in a single piece and lust be put on its shaft from the end. The split pubey is made in halves and can fjc put on the shaft at any point in its length* Pulleys are constructed of wood, cast iron and wruitght iron or 5^^ MOOIClt^ M.%4:ril!iK SH'»»* nvn^ 5teeL The wood pulley U tmih up of ♦ well (fluctl and secured together, tht- <1? The>' are provided with bushings for any size of f^ccured to the !»haft by a clam]j hub, Tliinj are ligli iron pulleys and arc well adapted ici hi^fi sfieed little tised in machine shops. Cast iron pulleys are, when f»t larj^t: diaineter. l>ecau^* of the severe shrinkage strains in the jihould always he balanced, and when of extra wi< should be provided with double sets of arms as shown Jir* The sleci rimmed pulley shown in Vi^. 651 is ciimin| FIG. 650, extensive use. It consists of a cast iron center or spj *heet sieel riiu riveted tt) the arms. It is a light, strong pSl! from strains and well suited 10 all classes of work. Pulleys are "tight** or 'loose/' depending on whether t to Ik' secureti to the shaft or arc to turn freely upon it, T **straight** or **crowned/' depending on whether they kIu fling or non-shifting belts. When used for very h« the rims are made extra heavy. When it is necessar\' to frequently stop or start a out sttipping the shaft a clutch pulley is employed. In Fiij fvhown a cut of such a pulley. The clutch is keyed and the pulley runs fr : - '^e shaft when the clu It, 1 M pnlV UELTING AND TKANSMISSH>X MACMINKHV. 5Tt "^R^R^tl from it, as shown in tlic fij^nre. f*\ sliding the sleeve lowarcl tlie hnh of the clulch the toggle joint closes the jaws irmly onto the smooth rim attached to the pulley, thus locking" le two firmly together. There are many fonns of clutches, differ- ig: widely in design, made. One of the most important features if a gnoic feet of free air compressed to 80 pounds per minute to operate it and wHl drill successfully holes up tf> 21/2 in'^ii'^e in diameter. X'arious types of rotary engines are a* ass of machines. They are not as economical ' lowever. as the piston types. s» MODKRN MACniKE SHOI* TOOLS. Hand Iioiftts are nuich usieel in the liamlliniar of weights vrt Iicavy for one man lo lift. They are comparalively slow and o*. ' scqnently not well adajiied to regular work in (ilaces where jmns- ' malic or power lioi^tj* can be used, lliey are more of tJie namit ' of a jobbing hoist, are compact . jiortable anendeni of each other, the tme bdng slightly largjcr than the other. I?y pntling the chain over the Iar;jiT ' slieave it takes up fabler than the smaller sheave lets out, cohk- no. 660, FIG, 66k fluently the hook goes up. One maji can lift from 800 to l/JOa pounds with this style of hoist. The gearetl hoist Fig. 661 is an example of the many hoists of this character that are made. It is a spur geared hoist with a suitable brake for holding the load* This form of hoist is more rapiii than those using a worm and gear and is comjiact, refjuirinjj a minimum amount of head room. With the better hoists of this class one man can Kft the rated load, Witli this elass of hoist the higher the speed the less the weight that can be raised with a given eflfort* l*ower hack sawing machines, an example of which is shff the teeth or hreaking the blade, especially if the work is of small diameter, thus permitting contact with hot a few teeth at each point in the stroke. Tnbitig is very hard on blades and should be cut with light |)ressure and saws which are somewdiat worn. Oil is not used on the hack saw blade. In Fig. 663 is shown a 'lialancing way*' used in the balancing k^gi a Mpfif of i4 from jor la 60 Wi tlif tank. Tm> cr laMoif dit htat, THr pfved mechanicaliy. thus cleansing, refining and makhig it suit- jle for use again. The reclaiming of oil which cannot be rlrainetl from the chips tf^hich accumulate in the pans of screw machines* or other lachines using oil on the cutting tools, is an important matter. Ilis class of oil is high in price and can be used repeatedly if eclaimed. The only satisfactory method of doing this is by FIG, 665, leans of a centrifugal separator, an example of which is shown Jn Fig. 665. In this machine a strong inner drnm mounted a vertical spindle and capable of high rotation is filled with be oily chips. The outer casing wliicb surrounds the drum prves to catch the oil which is thrown off from the chips by the itrifugal action. In this maimer practically all of the oil is umeth ie accumulation of oily waste about the shop is a constant of danger and more especially in cases wliere there is the V of its receiving moisture, as spontaneous combustion 5H UmWMS UACUiSK »UOP TOOL^ i» ver>' apt to occur. The only safe way to iitftpo*e of this mj. tcrial i* to Imni it at regular intcrwils^. WTiilc acctmiuUimi^ n [ «hoiil and nraal ttj|;etber. They are providefl witli Icg^ and a do0e fitting; ooto:. In caK* the waste starts to burn it is so completely cut off tram the air that the combustion is neces'^antv ^]i*w and nia\ tk A^ tected by the smoke and odor. The ^vMemalic ket-ping of stock anil tuul> in the niaduxif >htjp h a matter at very ureat im|xjrtance and one requiring for each particular ca«c a great deal of thought. Small tools, jigs and k no. 666, fixtures shnulii lie kept m a Ujn\ room umltT the charge of n cntH' ptlent icRil rcHJiii man v%'hnsihlc for tlic givitrg out, receiving, inspecting and repairing The ttX>ls slitnilfl he flistriljutefl on sheiv< ers in snch a manner that each article hu thus enabling the tool man to select it n possible loss of lime. It is preferable to general use about the sho)) in a place wl to view. Tool^ and fixtures of a special in drawers properly tagged. In the case of to keep them \vit!i the full special, that arc requirei IlSCELLANEOrS SHOI* i:oLII*MKNT AND C€ 525 orator then draws all that he recjuires for the work iji a single H antl save<^ the time and chance for error incident to drawing le tools separately- The stock room is an extremely important feature in any tcW organized shop. It should be well supplied with bins, lelves and racks for keeping the various supplies in a systematic aanner, and it should be in charge of a systematic man. The stock room should receive and give out all materials and ^tipplieSi keeping at all times an exact inventory of stock on hand. In manufacturing shops all stock parts which go to make up 4he machine or articles manufactured are kept in the stock room. This gets them aw^ay from the machine as soon as completed, and puts them where a quantity record of them may be kept, and FIG. 668. ihe least possible amount of time lost in getting them \\hen required by the assembler. For the keeping of small stock, as machine screws, cotters, taper pins, etc., revolving racks of the character shown in Fig. 667 are admirably adapted. Tools and work racks at the machines are very convenient- Fig. r>68 is shown an excellent form of lathe rack which has .es for work and tools, with a drawer for the mechanic's 4«t. A similar rack of larger size mounted on castors from machine to machine. Is shown in Fig. 669. ponvenient for holding work that is to be operated more machines, as they can readily be moved from -without the necessity i>( rehandling the w^ork. 'T may be had of wood or metal and -'nf work. 526 MUDIvKN AlACIltXt SHOP TOOLS. The lathe pan shown in Fig. 670 is intended (or use xmtitt the lathe» the upjxrr tray catching the chips and the bwcr on? fnr hnliUng work* It can be readily rolled from under the ma- chine for cleaning. It is of special value in cases where an oil nr water cut is Imug run on the lathe, as it catches the lubricant ii:^ FIG* 670. which can be drained off thrnupjh a cock provided for tl purpose. In Mg. 671 h illustratetl a form of pressed steel tote box or shop pan. They may lie had in a large variety of shapes and sizes and are admirably adapted lu the bukling of small parts FIG. 671. and ^ttpplies. Small hardwood l>oxe<; with suitable handles zft also well suited to ihii^ purpose. When an oil or water cut is occasionally desirable on work in tlie lathe, the simple device shown in Fig. 672 serves very fiicely and is much more convenient than the makeshift methods so frequently employed* CKLLANEOUS SHOP EQUIPMENT AND CONVENIENCES. 527 ;e cast iron plates planed smooth and true, and mounted ible legs, are very convenient for the laying off of work. FIG. 672. They should be kept for the purpose intended and not allowed to >e used as shelves for other purposes. TABLES A3(D t'SCFLX DXtA, Iht niAt!^ and data crmuMneA in Ms chaffer have bea ^lertttl with the vsew of gettii^ together, in convenieiit forra, the tatelated inionnatkjn to which the mediaiiic tnost freqncmiy wishes tc/ refer. I or Kwwn AS» kst-wats^aai h i II III llfr «li IS lilt TABLES AND USEFUL DATA. 529 TABLV or DICIMAL. BQUIVALCNT8 Or StHS, 16THS, 32l>8 AND 64TH8 OF AN INCH. 1^ .015625 il J6662S ii .615686 II .766625 A .08126 A J»125 u .68125 II .78125 A .046876 H J306875 II JM6876 a .706875 A .06S5 A .8125 A .5685 il .8125 A .078125 u .328125 Ii .578126 II .828125 A .08376 H .84876 il .60875 H .84875 , ^ .100375 « .360675 II .600375 II .850315 i .126 1 .875 I .625 I .875 A .140625 « .390625 a .640625 a .800625 A .15625 U .40625 u .66625 !l .90625 a .171875 il .421875 II .671876 II .921875 A .1875 A .4376 u .6876 11 .9875 11 .203125 if .453126 11 .708125 a .053126 A .21875 H .46876 ii .71876 u .98876' H .234375 IJ .484376 a .784875 u .064876 i .25 * .6 1 .75 1 1. DIFFBRBNT STANDARDS FOR WIRB OAUOB IN USE IN THE UNITED STATES. Dimensions of Bizes in Decimal Parte of an Inch IS u In i 1 ^^1 -4 ^1 II nt^ ^^ ^'1* "g a& d'" ^^ 000000 .4^14 .|flH7S mum OODtiJ .43:3 .4375 00(11] OOOQ .46" Um .30^ .4orj .40f^ uon) 000 .40054 AS& .3rt35 Xi .m^ ca* 00 .3648 m .aaio .348 .34875 m u jmm M .3UU5 .:«f4 .:3l2fi a 1 Mm .3 .seao ,300 arr awja'i 1 £ ^rra .284 .9836 .07*1 .lilt) ,^o&i^ i 3 .^f&i^ ^% .£437 .avs .21:1 .s& , ii 4 ^M^} £;}8 .£250 .2:ja .ao7 .^94375 4 5 MIU 22 .arjTO ,212 304 JJ1876 5 6 aasTJK aii3 .l»iO ,ltti 2111 .flE^lJS^ H 7 J 1128 .18 .nio .17(1 lliB ,1875 " 6 jans .ltt5 .14^ JflO m .171J^B K 9 .11143 UB J4Ki .144 JOI .m&^ » m .1111^ .134 .I35U J2M JH .I44»^ 10 11 .mm2 13 .1^5 , Jia Iftt^ ,1^ 11 IS .mmn IW 1 .K)65 .104 .1M6 .1003:5 !:>* 13 .OTlOril *OHa .0015 jm ja; jw.m 13 14 .054m4 0 7Ia AM U.IB fittJi 421.89 27JI 1«T ^1 ^^^B jL* aj» .ttIN un LU ijom \S& *n3| i«J» && 48a4B 2.71N U8I 1 ^^^1 In a.7« 1.11*7 1.41 1^ ijm tt sis 84 §1& 2J«9!i ^ 1 ^^^B ]|I UM!i l,«T 1.60 L» im um mi tskm mM MU8 tm tm 1 ^^^1 |Jl iM 1.35a L7t aaM him ijtw ^ mio M7S 73L19 814.18 2JU w 1 ^^^1 |Ll 4M 1.4M 1J» aiKi \si tll2 m n49 oaj8 7ejS0 2914 ^w 1 ^^^1 liC 4J52 LiffiS ao7 a97 1.129 9 28^ a94SS 61* 7*a a UBI 1 ^^^1 lis 4JI I.W tj» nm vm lU/> ft^ 2u,fin 97.20 89^ 791^ 800 tjM 1 ^^^^B^^_ 4.ei U»17 a44 ZM l.»0 MMl i^ S»M nM 90 J9 8S7Jf7 a.*2 li^ 1 ^^K m fijl S.074 a«4 4Jb IJW IJ7« warn 74.69 9a «0OA 841 84309 aaas tm ^^^^^^H OJS am 8^ »3i 1 1 ar» 94 JM 5W.H 9U0 znu> a4n am ^^^H ^ ^ 7.flT » «7. ] 31 97 €9 754.8 «Wl 29791 &jsm 8141 ^^^^^^H '<^M 7JJ7 an aoj» I., - :t2 1(j0 6 B04J iit:4 asrras sjm ain ^^^^^^^ MJ Ink) ajo 1059 IHJB l.*Siii 1,4>*:.' 3» 1(S.T fidO um 9987 ^ aw ^^H^ jD afl6 11^ 8a44 IMI lA a4 Idas 907.9 iifie ss» SJlO ^^B nZ ll.m D.ai 13.2S 4a8H ijrri 1.51fi 35 ua 992.1 W5 9JS1 ^^H sZ 1IJIU iijjd ' iai4 47.10 1.9M iJtr, ;iA ita.1 101 T,y 12B9 «08» a aiDB ^^1 lu 11, 7h ii.m u.m 6S.78 um l.,v.;i 37 1 \*', 2 l m ua4 1134.1 1444 84872 UMI UM H ia.57 \2M Jrt. 64. ZL ifi*c ;« uaft 119t9 1^ ass OJfl IH ^^B' ^H i».;ift 14 ID iMjirt 7«.Ta 9 091 MUfi 40 1».7 1299.9 1900 •3 ^^L 4S U.N ixm a>.*i5 01J3 2.121 1.651 41 12S.9 man 1991 989S1 m8 HI ^^^^^^L ^H4 li.9£l 17.71 )»Ji» \(f!,m a 119 IrtHI 42 m.9 13M^4 1794 740M8 9 491 ^^^^^^H lik.71 19^ ». 125. i^SM i.no 4:i iaft.1 I4a2je 1849 79ain 956? 1^1 ^^^^^^B fiLt !?'S a 4u n.5»i 144,70 SJ»1 i.t:j^ 44 ijiaf !r»5>.5 i^m K'}^ i'^rxi aiS ^^^^^^^ m2 fi.70 ai).*-ir> m,m 2.84S Lim 45 MIA iS ^^H^ fi|tt 18.00 «6.W XitW 190.11 aaiB 1.7tti 44) U4 fp ■^ aw ^B «i ' inm]:*f^?9 rin 210. 2.449 j.*n 47 147.; - ^i a«9 ^^ ey 1 ;0,ort 244.14 95 i.^e iH IfiOS V^J^ji xm inxiri tijm aoi 2« «r.s8 !!T4.iJ3 tJ^'O t.m] 4VI in.9 umj 9KU 117849 7. UBI « ^ thM 307.&5 2.&M I >4^^ aj 1W4 1903^ 2SU0 129000 7J0I1 8J9t 7 L'l.Wi,*^!** ^• »43. £.046 I 913 Notm-To tlmi tbe 4th power (or biquadfut e^ ol II aumlicr^ nmlilply Uiataqui^lf thu wjui^re. To lod ttie 4tb root^ oxtmot tbe ftqimre roo I twUx m mtscamktutk, ^^^^^ ^ ^^^H ^^Bl ^^H TABLES AND USEFUL DATA. 531 WnOHTS OP 8QUAJIB AND BOUIID BARS OW WBOUOHT IRON IN POUNDS FEB LINBAL FOOT.— KENT. Iron wciKhiniT 480 Itw per cubic foot. For steel add 2 per cent. Thicknen or Diameter jin Inches. Weight of Square Bar One Foot Lonir. .013 .0J2 .117 jaoe J8M 1.065 LaOB 1.676 1.875 2JM)1 2.553 2.990 8.768 4jei9 4.701 5.206 5.742 6.802 6.888 7.500 8.138 8.802 9.492 10.21 ia95 11.72 12.51 18.33 14.18 15.05 15.{» 16.88 17.83 18 80 19 80 2083 21.89 22.97 24.08 25Jn 28.87 27.55 28.76 80.00 81J» 32.55 33J7 35J>1 86.58 37.97 39.39 40 88 42 30 43.80 45.33 46.88 48.45 »)(i6 5168 63.33 WelKht of I Hound Bar , One Koot Long. .010 .041 .092 .164 .266 .868 .501 Mi 1.287 1.473 1.728 2.004 2.301 2 618 2.955 3.313 8.692 4.091 4US10 4.960 5.410 5.890 6.392 6.913 7.455 8.018 8.601 9JHM 9.828 10.47 1L14 11.82 12.58 13J» 14.00 14.77 15.55 16.36 17.19 18.04 18.91 21.64 23.59 23 56 ZiM »Jg! 20.60 27.65 28 78 89.82 30 94 3«.07 3:3 23 34 40 35 60 86.82 38.05 39.31 40.59 41.89 Thickness or Diameter in Inches. Weigrht of Square Bar One Foot Long. 65.01 56.72 68.45 60JB1 61.99 68.80 65.64 67.50 69.39 71.80 73 24 75.21 77 J» 79 JK 81.20 83.33 85.43 87.55 89.70 91.88 94.08 90.30 98.55 100.8 108.1 105.5 107.8 110.2 1126 115.1 117U5 1200 125.1 130.2 135.5 140.8 146.3 151.9 157.6 163.3 169.2 175 2 181.3 187.5 198.8 200.8 2067 2138 226.9 240.8 255.2 270.0 285.2 3)0.8 316.9 8333 350.2 367.6 385.2 408.3 421.9 4408 460.2 480. Weight of Bound Bar One Foot Long. 43.21 44.55 45.91 47J» 48.68 60.11 61.55 58.01 64JS0 56.00 57.58 50.07 60.63 62.22 63.82 65 45 67.10 68.76 70.46 72.16 7ZJ» 75.64 77.40 T9.19 81.00 82.83 84.69 86.56 88.45 90.86 9U» »4Ji5 98.22 108.8 106.4 ]ia6 114 9 119.8 128.7 128.8 1349 137.6 142.4 147.3 1S2J8 157J 162.4 167.6 178.2 189.2 200.4 212.1 224.0 236.3 848.9 261.8 275.1 2886 dOStA 816.8 33L3 846 JS 861.4 377. 532 MODERN MACHINE SHOP TOOLS. WEIGHT OF FLAT BAR IHON. ^ * THKitJMe^is m INCHl^, 5f 1^ M A H A H l\ H H Pi ^ 1 Itn. lbs. l\A IbB. Jlie. 1 itio. ' lbs. Ibe. Ibfl. it». tbi. M Jl ^1 M .4i JS M ,78 .S4 1 I .13 .m .40 ,53 .» Tfl JS L<« ' 1JB9 % JU .m .47 .1^ ,1» .as Lll J 38 IM i.» I .La .ilT .60 .74 .IK Lll 1^ L4« H4i 3! St 2^ 1 Jf .4^ M .^ iJiS 1J» L4T IM £.lt 3.63 t» IJT H M .11 Jl ,i)5| LIS 1.4S IM tM SLOT ^,84 an f^ \i M jsa -?fl i.ua 1.83 1JS» IM ^11 sea 3.15 SJA i!l N JS9 ^ M Ul« 1.45 1,74 ».«J &^ a.*H) 8.47 4.Ui 4jn i i M .A3 M isa 1.58 1.90 :i.si 3^.33 8.1« 3.7S 4.42* lur£ ) \ M .as 1.10 1 L3T I.n g.w* 2.:« £.74 3.4:! 4.11 4.?J U1 ^ I *37 , J4 Lll i.4T LM £Jg[ 3.©rt Z9$ 3.b# 4.43 5.I1I 1 iM M 1 JO .78 tJ» IM 1.97 2.^7 S.7a 3.16 S.SS 4.74 BM (LO a .42 .84 tJfi i.m a.u S.53 2.»fl 8,37 iSl 50(1 6M ill ;4 .45 ,m i.ai i.n 5.*4 Ji.418 ^ir3 3.A8 4.47 , 5.37 4JS ;.H .41 ,«& 142* hm 2.;?T 3.84 3.3^' 3.71* 4.74 5.«^ AM 7M ] Ij 1 Jj(} i.no IMf t.m S,liO £I.UO rut) 4.1>0 5.00 aoo 700 m 2 ..la LOl IM 2.n ^83 3.1a 3.«H i.SL 5^ 6J» TJT 1.1s ' nI j55 LH \M ^•21 3.t0 3.32 3H7 4.42 6 53 eM 7.74 aji 11 .ae LIO L7* gag sage 3.47 4l.kS 4.»3 5.7* 0.05 aio an % *0l 1.^1 igs 2.42 3i3 3»i3 4.:r4 4.^ U.II5 7J» $.17 9M 3 .«a 1.3ft i.m zm 3.10 aTB 44^ 6,05 6.^ 7.5* »M \nM >w um 2M ±n 3.42 4 11 4.7S 6.47 tt.ti4 H*I 9.5a Mm iZ M 1,4T 2:^ %M.% a,«a 4.4S fij«i 1 6v8» 7.37 aS4 lOJlt lis 1? .78 1.A8 2,.n 3.16 3.^ 4.74 5.5:1 6.:]^ IM 9.4T 11.05 ima 4 ,N LtW %M 3.;rT 1 4.£1 &.m S.«9 ft.14 ai:i 10.10 11.7« 18.17 i .90 1.79 2M a.s^fl 4.47 h. t.Cl{) H.QO lail) itm itoo 11(1] 6 i.iiei SLll JLltt 4:;t fi.L'ti 6.;^ 7.37 1 l!i.4i Iti^) I3.n3 14.74 I }m 1 11 S.:rl ;i.;t; 442 fi.rijj iVAXi :.T4 B.S4 liJ-6 I3.«ft 15.47 I lT*5i< i2 l.l*J £.3:^ JilT 4.i« S,7fl ' fi.i'fi f*.U) WJ>1 U.5^ 13^ lOJJl i.ji !|[7 IM 2.4^ niu 4W , lUL=i 7inV . K.47 ».tW l^.lil ]4.&3 16.115 IWlfl 6 1 1^ 2M 3.:\j fi.lJS B^ 7.&a 8,84 1 10,111 u.6:j iri.15 17.fle* 9^11 PLATE IRON. WEIGHT OF SUPERFICIAL FOOT. Thickness in imlH'S. | Weight, lbs. .a\vzr> 1.25 .(»♦;:.*') »'.519 Ami ; ;j.7?w .l2.-> 1 5.054 .15(52 1 6.:«)5 .1^75 7.578 .•J 187 i H.19 :S) IIMW :^12 1 1I.:J^ Thickness in ini hes. \Vei«ht, lbs. ,";, - .3125 12.58 •Hi= .375 15.10 ,V, - .4375 17.(45 H= .5 2UJl> ^= .635 22.7H 2«.ir, J»4= .75 %- .876 30J» 35.31' 1 = 1. 40.40 TABLES AND USEFUL DATA. 533 SPfOIiriC ORATITY AND WEIGHT OF YABIOUS MBTAL8. M BTAL. AlumiQum, (»i8t^ .,',,'. .......... wrougbt Qm^, Sbeet, Copper IS. 2inc £3 . . ' ■ Y ?llo w, Ckjpper m. Z\ no U . , " PlAte ,,.. ** Cast.. ..*» *' Wife ,...w..,.. .., BroDze, G iin Metal. . . , ..,.., Copper M, Tin !§.... .... atptierSI, Tin 10 *' Pbcitfipbor^ Bear] DMT M(-»ia Copper* ti®!.. ..». pliitt^ ..,».. ... . ** wjre and bolta.... .,. ... ^Oia» luirc, crts!; ......... ^. * . * .. . * , ■■* mvinmeiied ....«.,... ,.. '* i^ liirut* Udo. .« i ,,,......., ** t3l riinits llne...>.,., .* Jriiliiira. huimiKred.... ,. ....... IrijD. cLLKt, Kun metal , * . , , . . * ore] nutr.v, tneaii. I,,..,.. ... . '* wrt>ught bia ra* . ... ...... *' %4- rung bt wire ** w r4juif ht roUed pUlei .*..... Lead^ caat. .,.♦,»».,.* " rolled ....... ..,., ....,..», MefCiiry-40deir.'» *»»- ■■ ■■ -|-33de«. . -VWdfiff . , . ^^ '■ 21^deg.... .... *' cast .... ... ...... .......... PlatlnuiQ^ taHinmeroil .... , , '* uativrs ............... ... rolled E*NlLead ...i..,,*., .. tjilver, puit!., e4at .......... ,,.... ^ ** nftiTftfflprgd ........ 8te«U temporGd uQd tuundeeed " places.. - . - " emcible....... . ,. ,...,. '* BesMinier. .... .... — , . , , . Tin, Curniih, btttniiiered .... . , . . . *^ ** pure ^ncciist...... ..... " rolk'^l ..«••,.,*». Gravity. 2.«70 6.713 HJUO 8.1W H«t(J U*.258 n.4tw Id.'Kttt £3L(IO 7.;ffts T.788 7.TT4 T.TOt ii.S5:£ 8SO0 1I5.U0(» [{I.474 Ul&ll 7das 7JB0 7*%l 7.191 Welg-ht of a Cubic I neb in Lbi. .mm .mm .a*2a 3WT .317^ .81445 .70(R .wm .2ef/7 MU .JJ7K7 .4I0B .4119 .49JJ^ .4WW .4«ilf; .3183 .7^»l .!i7«7 .79*^g JI4 .I7as .880* .284 .a5*:i .2IS97 JS48:* Weigh I of ft Cubic Foot la Lba. 156.6 ltS.6 508. 51T.» 50U.3 518.5 5M.Q 5619 Sfifl.l 575.8 647.S 543.T 5«5.l 121M. 1210. una fH^I.8 14;^. 4868 48i.e 70».5 711.7 840J 1418. t ^5.7 R17.4 1171. U»e.9 1370. 5fif».0 e&i.6 057. 4mf 497.T 491U1 400.7 41$ 1.9 4SS,7 43S.& 449.4 WEIGHT or VABIOU8 SUBSTANCES.— KIOHARDS. Weight of 1 Cubic Foot in Lbs. Name of Substance. WelflThtof 1 Cubic Fool in Lbs. Brickwork 100 to 120 120 to 130 80 to 82 45 to 62 76 to 90 100 to 120 160 to 166 135 to ISO 62.3 to 62.5 63 to 65 60 to 60 Oils, various 64 to 67 114 to 116 Clay Acid, Sulphuric Coal Oak Wood Pine, White 42 to 68 27 to 80 Coke Earth, Loose, Pine, Yellow Air 35 io 45 EarUiJ Rammed .08 to .080 Granite 8t«am , . .... •06 to MU Sandstone Snow 5 2 to 6.5 Water, Fresh Wat«r. Halt Coal Gas. , Carbonic Acid .085 to .086 .122 to .128 Alcohol 534 MODERN MACHINE SHOP TOOL& A.VMan_ WniWelcli wlien OMt In "•^'fe^Si*"* OMtTmn. Zinc. Copper. Tgkwr .S& BUlMWMiT— Nmhii. LlML ia7 Its lift M.? 14.1 f. SI ULl Ml! ULt M Lfae. IM VLl KIl4 112 u HA ^ ' HoodurM... •* White. •* Yellow iMt umrt or hbat iir omi pocvd or w%jwLt^ Anthmrito I4ja> ntuminous 14,00) Fetroleum, llirht fteoi Pptroleum, hMvy ltL440 . reflncd iMn Fetntleuin, crude lyn Goal Get Ml WeterOat ajl|> TABLB or BSLAflTB TAUTB OT 1KHMXMHW0KO—. iluw. E. Rmerjr. NoiH\>n(tii«-ii>r. . VnliN\ Non-CV»iKliictor. Value. Wtxwl Felt I.ilh> i lifNUii, dry and open . . ... . . » wBlO lliiK^nU VixMA No. 2 .K3S .715 Slaked iime ...: .:..:;:. Gas Howe OtrtKm. A«ibeiitl with Tar. 8ew(tut(t .flD in Mloenil Woia No. 1 ^^^1 \t^t^ .,^ JI5 Chanke In lumps Airs|«c^ undiTided. ^ PROPERTIES OF METALS.-RirRARDa. Ntuncin of miiteriaK Wroii»rl)t Iron, hvjtp. ('art inm. Cast i^tcel. BoBsemcr stecK ** Tin, •* . Lead. Silver, Weiirht in lbs. of a cubic foot. Woiirht in : lbs. of a ■ cubk'inoh. Relatix-o We«|rht. Wafer, l.OOn Tensile stremrth Ite. |ier In. section 1 Meltiiur poinun 4a\.0 *:7 T.nio u.aoQ im I.'HIO .ail 73M) M.UO tm 4JC.0 .3W0 7.rtW iaa.oni> MO 481.0 .tHO 7.MI 9(MliO tm ,"447.0 .31« 8**» h» SrtUl J»l t im 4.VM) jao 9 441 ?\w.o .410 11 m AWO .:C« K urn TABLES AND USEFUL DATA. 535 1 ja Oil ■too,f 3jqTia ©no 9dui JO H^^naq :^ c w 1 liiij{nii[ ^ S 9 i: S § § 1! ^ i S S g f S g 8 i S S g g ^ ^ C 1* « 1* CO 04 5* ^ ^ 1^ r^ * ■ * ' ' ' * ' ^ & 1- «5 '^ K ■»! "Si "M -^ -^ ^ 3 EG il H ■Wl®K « B ^ imu^Tll i 1 i 1 1 i 1 1 1 ^ i ^ i3 £ g i§ |§ s ;; S S § jiiKunx^ IE, *|i(0.}d^itl ^ d 1 r « -; « »s » ^ « « ^ = S jj 3 £ ti a S K S" R !«■ if "Bsanil^iiq^ B §i^i^S:::|^^H^^i|i^8lii!|!| s ^]^il§g|siS|E3SSSI§gSis . i^ @ § ;:|i s 3 i s osi « o S § § § § i? . r^ ' * ^ -^ ^ ^ »| tl w -^ V « u5 i 1- ■*■ » o »< 21 d E2 ■«3f;fx»^J5„^„^,;«„^^^„g^y 3HRN MACUIKC SUOr TOOLS, itisiiiSfSiiiiiifiil 111 ilgllililiiiiiiiiHI ^ fiiiiiillililiiiiiil ^3^3 3 S 5 IS S S *e miiWKiiiiiiHi J I IIBiHfsftfiiiiasi rrTTT (D S"5 )^. X ;:^ ^ nt is: X. m ^ " •• •• ■■ -3 :i S < :2: "« < ss s - :? - S * s? ' ^ — •* ^ z 5 A I' O*!-® -^POH — : "^ ^ *" ^ ' "" . £ 3 l\\ i\n fill I If ^5 mi 111! in > Sir r- = = t S S - 3; < K a: ^ -^ 9I ^ ^ ^ TABLES AND USEFUL DATA. 537 TABLE OF KMSRY WHIEL 8PBSD8. Bev. per Minute Rev. per Minute Rev. per Minute Diam. Whee\ of 4,000 Feet. ^or Surface Speed for Surface Speed of 6,000 Feet. of 6,000 Feet. 1 inch. ifijro 19,099 2^,918 7,639 9,649 11,460 i5 ** 6,098 0,366 7,639 4 " 8.830 4,776 6.780 5 " 8,066 3,820 4,684 6 " a,646 3,183 JS? 7 ** a,188 2,788 8,274 8 " 1,910 2.887 2.865 10 " 1,628 1,910 2,298 U " 1,873 1,692 1,910 14 ** 1,091 1,864 ^'•S 16 ** 966 1.194 1,432 18 " 849 1,061 ^^ 20 '* 764 966 1,146 2S " 694 868 1.042 24 ** 637 796 956 28 ** 686 733 879 28 " 646 688 819 :W ** 609 637 764 :>2 " 477 606 716 ;34 " 449 561 674 36 " 424 531 637 38 " 402 603 ^ 40 " 38a 478 42 " 364 466 546 44 ** 847 434 521 46 " 332 416 49H 48 •' 318 397 477 a) •* 306 383 469 &i " 294 809 441 54 ** 283 354 426 66 " 878 841 410 58 ** 264 830 896 m " 255 319 383 THE SPEED OF DaiLLS. Cleveland Twist Drill Co. Diam. of Speed for soft Speed for '^ Diam. of Speed for Soft V '^ Drill. Steel. Iron. BrasB. Drill. SteeL Iron. Brass. ■ i« 1,884 2,12H 3,648 1 1 108 185 216 912 1,064 1,824 1^ 108 118 203 v* 608 710 1,216 1 A 96 112 198 k 456 633 912 ik 91 106 188 ,"« 865 425 730 'i 87 101 174 304 355 608 »3 97 166 200 804 520 80 93 169 228 2m 456 IH 76 89 168 /« 203 23B 405 1^ 73 86 146 h 182 213 366 70 82 140 n 1H6 194 332 68 79 186 H 158 177 304 1% 65 ^6 130 II 140 164 280 lil 63 73 125 130 152 200 ifl 60 71 188 }S 122 148 243 m 69 69 118 1 114 133 888 2 67 67 114 538 UOOERV MACHINE SHOP TOOL& TASLV or SUBi or TAF MUUA Tup Dimmeter. ThrMds per Inch. DrmfdrVThraML Drflifor V.a.8CmhnL H 16 18 ao A A Al t% , A 16 18 ao A U U A 16 18 A U $4 U 16 18 J4 41 H 14 16 18 14 A A A if 14 16 18 II U U A . 14 16 tt. U U il 14 M II K H . U U 14 M 11^ II tt . A IS 14 A n A H ., 10 11 IS it. H. H K u 11 IS A A «« 10 11 18 10 0 10 it 9i M K n II 9 II 1 8 II u TAP D«IU. SUBS. Fbr Gm Taps. "•ffiTorpS?"' Diameter of Drill. Diameter of Ttep or 8iaeofPlpe. OtameMrorMlL Winch 1 *' 1*: «4 - MACHINE SCREW TABLE. Si*n*w (iauire DiaiiR'tcr in 1 ! Apunixiiuato I Uiaojeter. Xo. Threads Siaeof Sizv. IXvimaK lierlnch. Tip DnIL 2 .W4£ fV .18 4» :) .1973 11 «8 45 4 .lllR «« '» 42 :» .uas 1 H » W A .1388 n » 35 7 .1j««) j» :e :« S .1«31 i: ;» 28 y .ITiB ^4 au 8 i»i JK8I 1^ C i: Jd«W J*; 1* 2 IS jam ii 1- 1 19 .»!:« 1. I'* r ** 1 .^Kfi ji 1* D =^ MU z\ 14 J 24 1 ,jrs: s W N d(s .lUV ,? Irt • p *i .4d& ii 14 K 91 .4Sfi» u ^' TABLES AND USEFUL DATA. 539 TRANSMISSION OF POWKB BT LBATHBB BXLTINO. Singrle Leather. Ilelt Speed. 000 ISM HP H P £100 mm 3I$U0 4,irNi H P 4800 5400 0QCK) Width cif JJeit. HP H P H P KT H P K P 0 IS 4^1 N 75 81 90 1(B las 144 H P i in....................... 2 in....................... 3 S 4 s « ft 9 10 IS 14 IB i 4 <5 8 m IS 10 IB m 8 « 311 4^ 4 1^ 16 as 40 m u A 25 ») 4f) 45 m m TO ^ 1 tie 48 M ISO 73 S4 86 I 14 XI m '^ i^ 56 &3 70 U m tl£ 8 16 S4 S 48 m 10 SO a In. .. .., ,. X 4 in, .. ......,* .. .. A in.....„,,,*,...... 40 e In, ^ a In. 9 in 10 In...... .... 90 too IB In. ... .. ............. 14 In...... Iti in ................ 19} 140 IW Double Leather. licit H^iwetl. 400 ax> UBUO 1600 SDOO 3iC0 ^SHOU 8200 aaco 4000 5000 Wiilthiif DelL HP HP H P H P H P H P H P HP HP H P 41) a) m IIMI ISI ItMl sot) 2Hfl ;«!> t*7U 100 H P 4 tn,.. 4 d m m u u 30 SB 40 in ii> i» 3i 40 4^ 60 7» BO 13 m 24 48 m n m 1« m m 4B m im 144 im> 30 1)11 4tJ QO m m m vm im im mi m , laj 141 ^0 28 12 56 70 S4 1 113 140 168 210 3^ «I4 Ml 13» UK) m Ta ») lue , 144 SIS 370 1134 ^ n\n IQ ill. ....... .... 7S lOO 11 m. W In........... ia» 3J0 30 In,.... 2)0 3* in. .......,.»...» aoo m in. 30 jn.. .......,.,, 1 450 40 n...... .'. .. BOO ROPE DRIVING. TABLE OP THB H0R8B POWER OF TRANSMISSION ROPE BY O. W. HUNT. The %vorkin{f strain is 800 lbs. for a 2-inch diameter rope and is the same at all speeds, due ailowunce having^ been made for loes by centrifu^l forci;. Biametei- Ttope. 1 In, m in.. min. M in.. 3 in. ^pi«etl o r the Hhjio In Pcct per Minn to. ia3o 3000 3500 iOOO 3&IXI 4000 4&00 5000 6000 Toai 4 « 4.3 5B B7 73 7.7 7.7 T.l 4,4 5.9 7r> « a 9 1 98 10.8 10.8 9.3 l».(t hi^ T.7 fts 10, T n 9 13 8 18.5 18.7 13 5 B.K 0.^ 13 1 14 a 10 8 18 B ^0 £1 3 tlA 1« 5 l^.H IS) 1 n:4 30.7 33.1 t&lA m^ aofi 80.8 38 3 ti^ IHO 2^1 m.t 338 m 4 m t 41 A 41 h m 4 2T.ft ^A a08 35 S 4^,8 47 B 51 3 54 4 51 8 SUO a6.s Smallent Diameter Pulley Si m in. m in, 13 III. 54 in. 60 iu, U in. 5AO MODERN MACHINE SHOP TOOLS. Mmuitmar or rvtatwD ibov iBAvmro at vunamn Prime MoYOr or Head Shaft oftRjIiiff Main Drivbw Pulley or Gear, well rapported tqr bearings. Iilamcl^r fif ^hmiU « m 160 LSS iilo m ZOO «e 230 m DO i«IS:::;:::::::: mi. In .....*... H P If* I« an ! ^ m H P a, 4 & 1 10 11 17 m tt 38 It AS a p 4 3 0.4 it Its ao 4£ 100 B P 10 an '^ if Si 61 4 4 «.o 1$ M Si as lAO H P 11, t U 1 m Wi 17* H P IS It U » 40 fti 118 P44 H P 14.4 18 f« as IS «1 M Hi i«i H F 10.7 IS SI 40 eo m M HP 11J lt-« St »4 H V 74 2 HP 1*J II Sis::::::::::;:::: 8 41 ?*in-....:.: ..:.. S &::;:;;:::::::: m h m fiS:;:; :::::;::; 414 In*-...*.,,...*... ! ■ Tin. : , . .. ti F fn m TRAicBMimiia BFriccENcr OF TUBim> noir shariiio at vtww Aa Second Movem or Line Shafting. Bearinga 8 I^Bet jkpart. Diameter of Shaft. Number of fievolutiona per Minute. 1 1 1 — 100 m m E.p" m SDO m £&0 2X5 BOO m » IncheH. H. p. H.P, H.P. H, p. ff.p. B P. B.P. H, P. H P,„ ^l « 7.4 i.0 lai 11.0 m4 liJi r 17.0 1«U| mo if^ 7M 04 too 1^17 14 A io laj ftJ flUO MA 2 8.« IM 131.3 I5JE 17.7 so ^i 14^ mo ms m «hi 1(K8 US }hM ISA SLJ mi ss,s mi 81.8 344 m 2r l^jtt i&a B JES 3& Si 31 {ifi m 41 u >^i 15 18 33 as SB 38 37 41 44 i8 B «ii J7 SI m an U ae i.^ 47 , AS 5« m a^, Sit }» ;U 40 M m m IM 75 B\ 8 m m 4« as flO m 76 tis 00 97 im ?'i ^ 47 fi7 m 7rt «5 l« 104 Hi t2SI m 2^1 47 60 71 ^ o.\ 107 lltl i;ii 140 l«i m ^M &» 75! fiH \m 117 188 I4tt im 17U m ^ 4 71 f* m v^ lis ku m 100 8i3 231 m TltANKMITTIN<» KKKlClEKt'V OK TI'KNBD IRON BnAVTIlIU AT For Simply Transmitting Power. DirnGBBKT BPKEIMA. Nil itilientf KfViTliitlonB |M9r Minute. DiiiiiiHcrufSUHft. 111) IL P. lea IfiO 17fi 5t«l S38 AST 3U0 S8» 397 B. P. 100 Ini'^M-K. a. P. R. P. H. P. H. P. If. 1». H. I* H. p. H. P. UP. !i ik" 8.i 10.1 1L« 13.IV l,'iL7 17.0 «K3 2S,5 84.8 >£? ! KH 10.7 123 15 n.i Sl» l^.if 2V.H ae^.ii StJ& 34,3 \% 10.7 lat Itt iM.; !!l.f» 25 ■5* ;i^ % m 43 i^ laa \&,d ltt.7 Sfej at.i :t] a^ 30 44 18 At £ 111 m M ^ :«if :ir 42 4«i [i» m 64 ^^ 1(f u a* Si :» 44 51 67 03 TO 78 .0|a ae m ^ .1^ 4.^ .'laJ tD m 75 88 90 ^i^ s?r ££} 44J 47 Tht ft^ , 71) 7M 88 09 IDA S^ 31 m , 47 54 i&i 7:i «J 03 101 114 Iffi =p^ 41 ^ m ;;t 1 Kl Ml HI laTi 13a 1&1 lOT :i f*4 07 BL Nl LOH t«» Ifi LtfS im ifn^ £18 ^IM ftti m Ki» 1^1 \m Lt^ti , IK* 2305 2m sao m ^m MTi m 1^ m* 111 :»0 ass 357 ?AS 313 ;ti2 TABLES AND USEFUL DATA. 541 m < « ^l39$i^^llli!g$9=lt^glSSii it !^ 91 » i^ -«■ "^ (- ^ « ^ >i s^ il g ig s^ j ^ S c § g g il-i Ci B d if a » 1 1 1 1 ' IS S S S ^ f* s It- a* 0 ro »r| l-H. s 1 ■ ililllll a; 1 G "a Si3gi|Sig & — EUSilBllHli iir, ^iii§is|§ ^ n 5 3 B^^^t^%U^U ^, '^^ggsssiiS ^ • SSI §35^ Si 'i\ s a s s s = 5 ^ a 5 s 3 1 d £> ssKSaiiSsisassssiis 542 MODERN MACHINE SHOP TOOLS. CAPACITT or BOUND TARKS AND OTX«INDBR8 IN COBIO WWB AND IN U. 8. OALLOIB. (FROM TBAUTWSIN.) Of 231 cubic inches (or 7.4806 gallons to a cubic foot) ; and for one foot of lengtb of the cylinder. For the contents for a greater diameter than any in the table taie the quantity opposite one-half said diameter, and multiply It by 4. Thus, the number of cubic feet in one foot length of a pipe 80 inches m diameter is equal to 8.7S8x4s31J12 cubic feet. So also with gallons ana areas. For 1 ffKit « For 1 foot A For 1 foot d 1 a In Icntrtb. s B 1^ in, leDiFtb. if i In Iei3«th. 1^. e 1=^ h 1^ 11 li 1 ii S 3 0. l4 B 5 Si 1 Q 1 J? 11 II' O 1 1 Q ^1 1 i n 0^ H .mm .nofti .msH «f4 .5^1^ .£185 i.«ao 19 hfifiS l.oav 1471 1* .tmist} .CM IT* .(HJ4() 7 .5833 MTA i.»e» 19M l.«85 £.074 UUft jxm Aiat^ .afi7 TM Mm .mm £.m 3U I, em £.1^ ii.a JL Mi5 Mii) .(1*78 m jS^Hi :sm t.mi 3"^ L7*« £.SttS 17JS 79 M17 MU .01(15* TJki MW^ M^i's tAm 21 L750 ^4(iS ITJI ! C .mtm .Otil* Ji|:a& *4 Mffi .turn tSA \ SilJt L71K £Ji£l \^M 1 % .omi .wai .m 4,0Sl 87 %m) 3.070 mrA .imf mt\ .fHHH iSlVi .^^^2 .ftj^ll i.ane s a.;oa 4je74 .Hwr*! Mtui 4.7H 'Ai tjm i.WO 3n.TJ »H Jrt75 .itttn .2inm 11 .fiitjT .mi) ^.B^rr ai a.sHsi fi.^l ^.n i .aOKt .(IWl .^ilt UH .*i:i;5 Mm (j.tO^ 3Sf a^eee , ri.585 4L71 ,m*2 .IHUl .IJO^ Uh .»5H:i .7213 5.3D6 'J3 tJW &,fl40 44.41 a .j*^i) ,M;n .:*r73 nn .t*71»'i ^irm n.tkis 34 ±mi «L:iii5 47,17 3^4 27UH Jft7il .^^ilil isf 1 ffJUl jfiM 5.B7tt ; iv^i 2.9 m «,rt8l 4f).I^ i .2917 .iiWi^ .Jffl+H iifH i.msi .aic^i \\,Tih an 3.(«tJ 7Jlij^.* tUM .Hl^ ,f»T(17 .5rjj* lu l.(KJ ,i»!!|8 G.]^ 37 a,0Kj lAm l^^M 5r .iUSl .(w;3 .i^"^ u^ Ll:^ .f»(4(i 7.4;«i lis S.Hirt 7.^5*0 m.m *4 .^mt Jft>H5 .T^U 14 1.1157 liWW 7.fl«7 3fl ^.m\ ti,^»6 mm j^^ni .IKfcTi .t^ll 141^, L^IH LH7 B.rj7M 40 S.ltti **.7ses A5» 4^i .m^^ J 231 .tftfUsTi 15 l.S^i\ L!&!7 ftjyo 41 3.4Ut 9.i4{e mM /> Am .i:mh l.CJ^t 1 r>h, i.ia« 1.311^ «».»}] 4t 3/j 9,080 7tM fili .mfi .lr*J3 \.m 10 ].aLi;i L3t»j 1IU4 49 8.r,8» 1IL084 75.421 614 Arm JfjTid 1.:£H 1^4 i.;f75 L4H.'i 11. LI 44 %m& la.wo 7\».tfl m .4rtti* .imi ].:(!» 17 1.4 IT \^'n 11,7^ 45 xim 11.044 Ha.iS U mv) aw? ijtai 17^ 1,4fi8 K070 nM\ 46 'A.\m 11. mo Wri.Ifif £!S .mm .am j.r^ IH l.fifll LTiu i;i,^ 47 3.0 Irt \t.im flfj.l^ Mil .g«u J. 7^4 1 1*^J€ l..''iia 1-Krt7 13.1*7 4H liHI) \t.Bn HJi£ CAPACITIES OF KECTANOULAIt TANKS IN UNITED STATES GALLONS, FOR EACH FOOT IN DEPTH. Pi Leiitfth of Tiuik. Ftel Ft. 111. Feet Ft. In. Feet Ft. In. Ft'et. Ft. In. Feet. Ft. In. Foet. Ft. In. 2 2 6 3 3 6 4 4 6 5 5 6 6 6 6 7 2 - 21».!<2 :J7.40 44.88 52.:J6 59 K4 67.;i2 74.81 82.29 80.77 97.25 1(M.73 2 « 4»5.7r» •VJ.U) ♦k'».45 74 80 K4.16 93.51 1(J2.86 112.21 121.56 i;J0.91 :{ tiT.:{2 78.r>4 wr77 1U).99 112.21 UJ.43 VMM 145.87 157.(» :i « 91.64 104.73 117.82 i:«).9l 144.00 157.09 170.18 l«:i.27 4 — 119 09 ia4.65 149.61 \U.hl 179.53 194.49 209.45 4 () 151.48 168.31 185.14 201.97 218.80 235.«« 5 187.01 205.71 224.41 243.11 261.82 .5 (5 .... 220.28 24er cu, in. .Trvuie X . "rars = foot pounds. Kilcwraiiinies x 3.1046 = pounds, KiioKi'iimQieB X ^.3 = ounces avoirdu- pois. KllogTftmmes -^ IMG 3 ^ tons (S,(0) Ibi.) Kilogrammes per tci. cent, x 14.2.^1 - Iba. i*eT 9q. in. Kilo^i-aiu-metcrs X 7J!S^ - foot lbs. Kilo per Meter x .672 = \tm. i»er foiit. Klio per Cu. Meter x ,(W2 - ibi*. fxf-r vv. ft. Kilo per Cbcval x 2.3:« = lbs. per H. l\ Klio- Watts x 1.34 - Horse Power, Wtttta -(- 746. = Horse Power* Watts -+- .7:^73 = footpounds pcraooond* Calorie y H 908 = B, T. U. Chevai vttueur X SUBBZ = Horse Power, ii 'eritljfrade X 1^1 + 32 =r deffree Fubren- licit. Franc x IfiQ = Doliars. Graviry Paris ^^ 980i94 centlmetors per second. DATA OS) WATER* oum ItH. 1 cutnk' foot or water ^....«tit4»*«.^ «•••! 1 cubic mth of wa't-r =-...*-.. -.,.....* ... 1 traHoQ c»f waicr = ,.....«,,,..,,.. »«*......,........, 8J88 Itw. 1 gallm of water.= ,,.,,«.... ,, 01. cubic iiu 1 CO bk foot of water =. .«,.....«.. 7ABd ^lloti^t. 1 poimd of water =.... — .- .... .,,.., ................ 27.7 cubic m. Tlie al>ovo data is calculated for dletilled water at 40* Fabrcnliejt. The pre*«ure of a column of water in pounds i>er s^jUHrc incb iseqiiui to the bei^t <0f the column in feet raulliiplicd by .4-C]. The presHitre per square foot is eqiitil to the hclt^ht of th« .^lumn in feet niijlti- piied l>y *S.44 The powijr rctjuired to elevste wat*rr is eoual to the weight of the water muHiplied by tiie heiiyhtin feet throujfh which It in llfled tfo^>t pounds^ divided toy 9:it(]b). An allowance of 'Jl& per cent should ordinarily be mude for iricdoaal io DATA OW POWEf&. The ITnit of Work i.H the foot pOund or the work necet»ary to raise a weight of one pound one foot. The Unit of Heat 1^ tlie firltii^h Thermal Tnit or the amount of heat neoeeeary to raii^e the tcm(>erature of one pound of pure water from, ;©" to 4l)° Fahrenheit. 'Hie Mechanical EquivaJent of tmc Britip-h Tbermal Unit of licit i« TTH foot pound! of work, and upon this value iire Itesed all btiat atn3 power determlnaitiomi. A Horse Power is the amount of work necessary to raif»e 33,(100 pounds one foot Mgh iQ one tninute. It l5 di'p<^"^t*nt npuri three fairtors : force, distance and lime. Indicated Horse Power is the aiea.Hure of the work developed ita the oyiinder Of MJt engine and equal to the foilowintf cxpreesion ; Horse Power == PrDs»ure x Aka X Double Stroke X Revolutions 33^(XJi> ■where preasur© = the mean or average pressure per wjuaro inch on the piston; Area ~ the area of the pii^tc^n io f^quare inches ; Htmbie i*irokc — the distance traveled by 'the piston in feet for each rL-volutioo, and Hi-volutions = the number of revolutions the eu^ine makes in one tninute. la thLn expression the pressure and area reproMtift the lor*.^, and the stroke and revolutloos the dlsitaiiec. Urake llnrsc Fv^wer is the tnca.Hu re of the p«jwor given off at the shafts and la lwaysie«« than tlir^ linlit jiteil hnn«o power by an emoant equid to the work ncccflsary forcome the frictloiial re^^tiinci^ of the entwine. In njeajsurin^r tlie brake horse rn suitable brAlco ii-i applied to the Uy wheel of the engine a^ shown in Fig. (173^ 544 MODERN MACHINE SHOP TOOLS. A band a a a a of rope, leather or steel is placed on the wheel. The rod R attached to the braJie at the distance L from the center of rotation holde the Inake fna rotating with the wheel. This rod is attached to a suitable aoale beam bj mesu of which the null P can be weiffhed. By means of the nut H and screw 8 the bnlu oaa be adjusted to absorb the full power of the engine. We then have a force Pacunff through a dutanoe represented bj the radius Lud FIG. 673. the number of revolutions the wheel makes, or, in other words, the distance the point J" would move in one minute if free to turn. force X distance P x 2L X » X N The brake horse power = horse power = = -^— — — ^— — 3:3,000 foot pounds 83,000 when P = the force in pounds ; 2L = the diameter in feet of the circle through which thf toiie acts , n = tlie constant 3.1416 by which the diameter is multiplied to obtain the circumlerenca, and N = the number of revolutions per minute. (Kl,^5ii>r ;;Pi! '•-1, ■^^ti^idi^. INDEX. A Addendum circle 465 Adjustable hollow milling tool 'JU8 AdJuKtable reamers 114, 120 AdjuHtable limit gauges 1>1 Adjustable dies 13« Advantage of radial mills 318 Advantage of collapsing taps 133 Advantages of expansve mandrels. . lo8 Advantages of patent lathe tools. . 201 Alining shafting 512 Angular and notch gauges 84 Angular milling cutters 33«, 339 Angular velocity 463 Angular drilling 41."> Arl>or8 154 Arbors, milling 348 ArlMirs. shell end mill 346 Arlwrs. thread 347 Arch stays 462 Automatic gear cutting machines. . 384 Automatic screw machine 191 B Rack facing 415 Back gearing, computation of 167 Hack gear, friction IJU Hack gearing, triple 167 Hack lash, eflfect of on taper turn- ing 230 Ralancung of pulleys 521 r>a lancing way 521 Hearing, shaft 511 Hell center punch 220 Hall turning 243 Belting 41M) Helting. care of leather 493 Belting, double, triple, etc 492 Belttng, examples of drives 497 Helting. hides used for leather.... 490 Helting, leather 490 Belting, leather strongest section of 492 Belting, methods of lacing 495 Belting, methods of lapping 494 .Belting, power transmitted by 493 Belting, preparation of leather 491 Belting, reasons for running hair side next to the pulley 496 Belts, run of on pulleys 501 Bevel gear cutting 365-387 Bevel gear cutting In milling ma- chine 365 Bevel gear cutting, selecting of cut- ters for 382 Bevel gears 467 Bevel gears, laying out 474 Bevel gear planer. I^lgram .392 Bfvel gear planer, (ileason 392 ■ ■hertrlBir for nlaner 209 4.50 450 451 250 holes in heavy 420 268 I Horing mills, horizontal Horing mills, relation to the lathe. Horing mills, universal I Horing mill work, w»curlng ! Boring parallel holes In the lathe. I Horing mills, vertical 'Horing, setting up work for I Horing spherical sockets I Horing tapered holes with boring I bars Horing tools 200-202 Horing work secured to the lathe carriage Hox cut-off slide Hox tools Huthng spindle Hushings. for jigs Hrazlng furnace Hrown and Sbarpe tapers 26<5 2(1 > 2t>l^ 2til^ 25S^ 264 25:'^ 261 ■20;i 252 20l> 207 425 41(> 34(( Circulating speed of pulleys 514 Calculation of cutting speeds 224 Calculations for Indexing on auto- matic gear cutters 38(^ Caliper dividers 220 Calipers 64 Calipers. Arm joint 64 r allper gauges 6(> ( jilipers, hermaphrodite 6H Calipers, how held 65 Calipers, keyhole 6H Calipers, lock joint 64 Calipers, micrometer 70 Calipers, recording 64 Calipers, spring joint 65 Calipers, thread 6H Calipers, transfer, types of 64-6H Calipers, use of 65-67 <'allper8. vernier tiH Cam cutting attachment 33;i Cam milling, example of 'M(l Cape chisels 2i^ Case hardening 44H Care In heating tool steel 446 Care In Indexing 35.'i Care and use of drill chucks 151 Care of centers 23*^ <'are of files 45 <'are of lathe centers 181 Care of mandrel centers 161 Care of surface plates 54 <'are necessary In chucking 25.5 Care to exercise in putting earing8, form of 221? Center l)earings, lubrication of . . . . 222 Center gauges Hil Center head square, use of 221 Center reamer, combination 22*^ Center rest 225 Center rest work, example of 227 54' INUKX. • 11'' I '•. 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T'-ni|' ■«■ • : ..■.{ i l:l-i-l. if!Ji|H IlIlL "I ■■ ii.-: .■!■■;. k- • i'"t •.. ir.iilih.' iiiii> hilif • •i't :". -iiiiiii: i-i.'nk !■■ .■■iii:i ' i"ii ■ i ii:» I i«inni-i- i.i.'.'.iiiiiri..ii ilrill "iiKi I'll"' M ■..-, ■.:u;f'i ■•! ' ).ii'-!> ..• I .iii,i'i«'ii -'iti;ii'-- . . . ■ ■ii'(iji r i-h ■■' wi'i- LMM.'i' '• .. iTjMli-.Tl « I ■11' »i'-« ■ i."-i.iii| i!ii|«-\iHL: . . '•tll|M|-|M'l I'"' .,■ .1. .--. •! .:■: ii. •!.. -h.-i- • .:i.|.-,'.i : .:j ..■ ;..-ii\ _-.•.■ i ■!.. . ! -. r..|.;.J '.T.i-i-.ri- ..•■ .. . •• j;ir..|:;.j .■■ ■ ■! • =.!> I !•;. i:.i 1 1^ •J 11 t'.ii :;iii» i i i ]■■- . J.n I Is _ I IV I \r, !!•:. :;*.; rtii .iii:: Ik'vi-I ffonr i U! 1 lliy I'll^jfS riitiiij;; «liiitiilf ilm'U'l."! I 'lit tin;; k<'.v uii\ >• . . . . < 'lit till;: worui ;;>mi^ < ijtllii;; <»fr inui iii(i<- . . < UMiliU slM.|«Js « imlii;: off I'H'N • 'inlii;* «.Ii N. «;iitilii • 'iiniujf simimIh. »■:;.•<.• 1 Mt ;|ii;i Njili-.'i I ir»-ii;'.. . iy.-|..ii|jil .■ :; ■.- ' yr|..i«lii| ;.-;n iiij -\ -r- t'\rh,U\i.l TtMitli . i:r- i - • '\ liinl»T iHjriiiii. * vji'i jil «'yliinli-i- linrin:; iii.pJu: < \ limlrlca] ;:riri(liii;: . JM II :\:n . 471 v.: 4A -- il 1.: ; -J J ij 1' J 17*1 .M7 D Ilia for spirsil u^-ars xia Kii waff-r i«-liiiliiiiri 'ii f'»r< «■«! m i'liiiiiii'ii ifi h'ii>«' iM.\\i-r .... • ■iiiiiiinii ill uoiklii;: tit iiiiiM'irjil jiliih >i:ilii'iliil |i*iili' i-I.ist-N . . . . ijaijiMinl 1 1 1 •< lii' siiikinu iiiii« iiiii*' . . . lii'f.. :Hljiio:;ili|i* Ml'- t „,, i-liixii*'^ III . ... »i.-N. ••»r..,f ..r ii'riifMTlii;: i»ij . . lii".. - il ••iM-fiiii;: MM«i. liiiw «Iia: |M'ii*'<| »!•••«. •i'lll'l i|»'*. iiM- ill" (ill (ivt-rsi/t' KTiM-k. •iriii'n«ihiiis t}{ Infill' . . . . 4*: v: . •:^x: ... 41*:. ■ . . Ji ... «: . . . 3:i. ... i:w ... la.-. ... Uii ... l.:7 i::»; i::s . . n». 1.. l>ivt'ihii; iMf'iliaiilsiii on aiii'iiiiaiic I i:*'itv rutt»TH ;{*fi; i »f»'^.s. <)arn;» '.'11 I».iL'S. til.- 2U il»..L- iImuI.Ii. i-nd 211 I »-.--. huh.- j:u I|»«>L'->. ••.'!' «f lit" li'Vi'iJi;.'!' «*n 111*' unrk Jin ! -..III. I.. . »,i ti!.-^ i'. I".ii.!- Thi":i«U. iiiTjin;: nt '2'.'.:* • "i:i IV Mill:: .'"i ■•"• ;m!!W liiiiiL'. .'H-iiiriiiV III 4U * " *• I Mil \\ iiru' "1 k»-> P' . . ". 4" * ' •'■ |ii:i'.-jtij o\i'r i-fiif.'i- '2'21 "■■i li:-.-,Hi!-- .-iiifi ii'iTiiiiillir^ tiiim :■■ -^ tj,. ;-^ b ■ :: I*;::- .!'::i \:\i '• ]•■■'•• .i! li ;a|i lioltiiT". ri'v«'r*.inj:. . . l^^ -'•• In. I- :iiiii tap linliltT'*. iiiil»t»niiinv ..f 14: 1H ■ -■•■ l. ii:- ■•■■■..-k* ... i:hi ' - I ■■■■ .f-M-k. ■ ■ri«-^r..,"'. n:» ■i". T- •.■■!, . Ill- .' ■ '■ ' < ■i!. !':-.:i.-;iM • •II .... . 11'- . ... 4H :' i ■• ;:■ - ...rik- jllV - ■ ■.' f i •i: .^^..v.,r< 14: .'■I 1 • r/. .|..-.-.N. 1 :;.• for . 11" _ ■ ' ■ -I ■■■■: -i/-- . . . . 1"«' _■ ■ '■ ' ::■■- !::ir .. in:: 1 ..; r. ■^-'.-.i ',.,!.... loci I in:: . . 11-' -■ - ■ I' ■: i'.j ;r-:.. 1 .'.'.i-W, 111:; h -p-'-i ... 4<«7 ■■ " !" !i..l.- in I .lat.-. . . . 41.'. . . . 41H J _ ' ■ ■ ■■. . ; ;.tj. ;.. .. . . . -ii:. ;'.'.i7 |.n-iin>jiTi.-. . . . '.IS -Mii'lanl pji' K- «lii ill till ■J4'.i . . . 411 . 41" . -:4»» INDEX. 547 Z^rllliDg macbine, manufactures.... 400 L^rlllti lur brEKs work 110 L>rlll8 with "coDBtant" angle of flute 107 i:JiillK, forced 100 fr>rlllH with hollow shankH 108 OrlllH with Krooved shanks lOi) 9^>rlllM. causes of inaccurate work with Hat 104 SlrlllH. panjr 400 lirllls. horizontal spindle 4or> lirills. uiiiitiple spindle .*<0l» l>rllls. oil iul)e Ill DrIllH. oil tul)e, use of •J4.S Drills, portable 4n.-, Drills, radial 401 Drills, rolled fOO Drills, straight flute lo< Drills, three-flute 107 Drills, twist 105 Drilling tables, universal 40.S Drilling vise 408 Drivers, notch lii:^ l^rlvers. nut -ll' Drivers for threaded work "JIJ Drivers, pulley -!•< Driving ttt, allowance for '2H'2 Driving fit. definition o( 2&2 Driving large work on the mandrel. 100 Dummy, use of in turning cams... :i40 Duplex gear cutters :{S3 Duplex milling machine .'{17 Klectric transmission of power. . . . Kmery wheels Kmery wheel dressers Emery wheels, selecting of for any class of work Emery wheels, speed of I*3plcyci(»IdaI curve Effect of ."ily 429 437 1,}0 130 471' 440 4<; 140 474 10,-, 470 .-»o 105 2117 372 258 307 370 374 370 412 411 carlNjn In steel Effect of sand and scale on tiles.. Effect of tempering on dies F^flldency of toothed gearing Elements of lathe Elements of spiral gears Vsn6 measure gauges Engine lathe Example of center rest worki Example of heavy gang milling. . . . Example of heavy turret work .... Example of slotting machine work. Example of cam milling Examples of Jig milling Examples of vertical milling Example of box Jig Example* of Jigs Example of turret facing '^m Exercise of Judgment in turning. . . . 224 Expanding mandrels 154-150 Face plate carriers 255 Face plate chucks 218 Facing In lM)ring mill 272 Facing work In the milling machine 303 Fastenings 450 Fasfpnirgs for screw threads 125 Feather k<»ys 45,5 FoRther. sliding 455 Feeds, automatic vertical for shap- ers 285 Feed gear reversal 173 Feed rods 171 Feeds for milling 350 Feeds, geared 1 "*f Fellows gear shaper .381) File handles 32 File holders, surface 32 File teeth. elTect of form of 27-1:8 Files, annealing of blanks 25 Files, blank forms 23-24 Files, care of 45 Files, cleaning of 44 Files, cross sectiuess 25 i^Mles. hand cut 27 Flies, how held In operating 31-.38 Files, lengths 23 l^'iles, machine cut 20 Files, names of 22-23 Files, necessity of belly in 29 Files, pinning of 45 Files, preparation of blanks for cut- ting 25 Files, racks for 40 Files, rasp • 25 Files, safety edges on 30 Files, selecting of, for any class of work ,30-34 40 Files, single cut 25 Files, use of chalk and oil on 45 Filing, dirci'tion of strokes 34 Filing, effect of narrow surface on tile teeth 34 Filing, flilets 37 Filing, flat surfaces .35 Filing, interior surfaces 30 Filing, morrises .38 Filing, position of work for 33 Filing rotating discs 44 Filing rotating work 41 Filing, position of workman 33 Filing s<]uare corners 37 Filing S(|uare and round holes 35 Filing tliln work .3l» Finishing cuts after roughing 253 Filtering of oil rt'2H Finishing for planer tools 203 Fitting surfaces by "iH^ddlng** . . . . 52 Flat drills 103 Flat keys 455 Flat turret lathe 104 Fly cutter 342 Follow rest 227 Forced flt. deflnition of 202 Forged drills 100 Formed cutters 243 Formed gear cutters 381 Forming tools 207 Form of center )>earlngs 222 Forms of cold chisels 20 Form of fltites and teeth taps 131 Forms of hammers 17 Forms of scrapers 48 Frictlonal tap holders 147, 140 Frictlonal gearing 403 G (;ang drill work, examples of 410 (vang drills 4(N) (Jang drilling Jigs 417 Gang milling cutters 313 Gang milling, example of heavv. . . . 372 Gang milling, importance of.*..... 313 Gang planer tools 201 Gauges, ad]nstable limit OO Gauges, angular and notch 84 Gauges, caliper 00 Gauges, center 80 (iauges, corrective 02 (sauges. depth 80 Gauges, drill 84 (vauges. end measure .50 548 INDI.X. of (iiiiiKCH, nut aiKl wukIht (tUti^i^H. pliix uihI riiiK <;aiiK4*H, MiTutrh ;<'s. staiuhird our<> in uk«' of. . . (iauKt'H. KtanK, Htandanl ilinMid (iau;;*>H, Hurfat-,' («auK«'H. tliifkncKH s. lhroaM. wlro ar cut tin;;. tt>inpli| (l (it'arini;. fririloiial (iiNiriiiK. Involnto s.VHt«'in (l illals on f»M»(l srr»»wh. uho of (ti-aduatc machine dialM. valih* of. . iirin. «l!i'*sl!i«nt inn uf -I.M'p f.Mpi'lS . . |.'Ht:il.h. 1....I ;t iixliti ( •riinlii'.L: < Iriinlitii: «;ili.>.li»ij Criiiilitiu • ii iiMlt'i. I ii iinli'i-. II ll;i. k -;i\N '.l:i.|.'- Il.l.k '•:i\\ l.l.l.• ..r llMiMii'-: -. .Ii'-viiij jiii'l I •■uritKliiiL: . . ll:.li:lii.'!-. i.-.I-.^ ..I li.)lK!:l.-l li:in.l|.-^ il.':'.:ii." -. •!;:(. Iiiiii-' Il.ir:":i. «-. i .li.-Mi;:i ! i.- Ihii .•■ "-. \'>-i .'i! •■'■ Il..:!.l ■ ■•• ■.•"- ... H..M.I .;.;-^ lljirii!;.-. ■■! '..!• illH'^. . M;i:.1.-m:;iu :!■ .i! lI;,i.|.-niMj in -'.•.•! I|.-;iT. ui.i! ■■• Il.-jiiini. -•;■ -'••« ! .... Ih-aiiMi; "'. ■•■■'I s''"i. « .i?.' in. . . . Ilfnn:i{'Iii."li'.- .■:'!ip.i-' Hj.lfs ms.mI '..r l.-.-i'li.T ;.i-liini: Hii:l, ^|. I niillin- ;i t 'a-linh'tit . ."..".l . |Ili'u.< on plaiivr inaiiipniatitiu Ilobbinf; marhlnt' liolis. worm llt>lHt8. Iniud llolstK. imiMiinntii' llolluw hoxauou riirrt'I ia tin- Hollow niililug tool. adjtiMaiiii IIorM* pUWlT. ill u lie liorsi* pow«'r. detiniricu oi . . 1I*M->M' powi-r. indUai'-d ilorM> powi*r. mi-asniiim ui. ilow to lind tap ili'lU sizi's . How to sharp**n dU's liypfK'ycloidal ciirv*? . . ..Un. :vi', ••4: •'■4: ill :;.s(i 4i;4 47.» n;;t 471 4 74 4r.:{ 4(1 1' 4i:\ 471 4fi7 4f;7 M'2 :i7S IL'.. US 4*J.s \S\ \-a:{ I -Ml i I'JS \S.i i.'.i i::7 :2\ Iniportant'o of ilrili and tap holdirs. ]\f, Impiiriani'*' of van;; nilihni; :,\1 Imporiant'o of ):rindin}; ^-^^ Im|iortan<'<' uf kcfpiii;: snuip i .irti-r.. .Vii; Importano* of niiilin;: niai-nini-o ... :;ij Incnas.' iwl>l In tuilJs ii,', I nd<'|N*ndoni oiini-kN jj;, lnd« xin;;, ran* in .ca IiKlixin^. r»'nt«*rs ::::,■• Indexing;. <-niiipoi:nd ;;,i Inilcxlnt:. diffi'i-i'mial y^* lnd«'xin;; on autunia'I*' ;;rar ciifTfr*. I'airnla lions for Indi'xlnK. I>lain Indfxln^. nth* for Indicator, iisp of ti'^t lntlu«'nci> of form and numlMT of t*»oth In n»an»«»»w Insldr mirroiiuMrr rallpt*rs Int*>rnal Krindinu Involiir(> ftirvf InvnlntH tooth oiitlln*>. nppniximat- nit*tliod of layln;; out HIS ::v, :tj4 K 111 SI 4rtT Jacks, planor M*) Jijr. Ih)x. t'xamplf xamplc itf :!74 •.»:> I IMI .'iL'o IS is 17 is 17 .". ! S r. Key rule bliM'ks '.*' Ki'v scatcr :;(iK ' Key seatcrs. portable iUl 1 Key seat in;: in a sIuiimt :':»»? Key ways, iMiitlnj: of . . ::«14 Kt'ys. dr.'iwiim iif 4'7 KeVK. Hat I.M Kc\s. ^'11, Iiead I.'>7 Keys, ronnd 4ri4 Kevs. taper of i.Vi Key.v;, WnodnifT I.Vi Ktiee |>late. >:*»cnr:ni: w»»rk t«» 2.'i4 •'■'nee plate, nse nf :{7r. Knnrlln^ tools lMm; 'I 1 •_".« IS 1 1: I P :. I . n:: I.; I.:iri:.- micrometer callpors. l..-.pi'iiiu' P.HI P'T ;;u.'» I .-! • i . i .M !.• I..i:li. ,..N ::•• 1 1«« ^•■:ir I aicnlailoiis. . , • L:-a!s. fomponn«l. . . 74 |:;s 4:!:« 1.;.-, p:;i ]^\ 174 17:. 17;> INliEX. 549 athe chucks -14 Athe, (limeDHlonH of ITY 4ithe do};n -10 ^the. elements uf 105 ^tlie, eD};ine 165 ^the. Rap 1^-4 .^tlie heatl Hiock 16o ..A the. liui>ortance of Hi'A Latli^. UKiuitur 181) Lathe pans 5::5 Lathe, pit 184 Luthe. pulley 185 Lathe rackw 525 Lathe, relationship with other tools Uili Lathf, sp(>e(l or hand 104 Lathe spindle l>earingH 100 Lathe tail stock 168 Lathes, testing of 179 Latlie tools 197 Lathe, tool makers 182 Lathe t<»ol8. patent 200 Lathe tools, patent, advantages of. . 201 Lathe tools, threadlnt; 203 I^the tools, s*>ttlng of 199 loathe, two spindle 183 Lathe, tiirret 180 Lathe, turret chucking 188 Lathe, wheel 184 Ikying out l>evel gears 474 Lead screw 169-174-177 I^ad screw nut 174 Lead screw threads 177 I^utlitM^ b--liiiiLr 490 Left hand scii v, cutting 234 L<»v(?Hni^ \Vfr»iJ;:"s 29t> Hui^ar vi-hir] i v 46« Line of HOT km In gearing 473 Link Jf»n h'-r l-lt liiii 496 Litiln;; up linp Hhuftlng 512 Link planing attachment 295 Limit gauees 61 Locating drilled holes 112 Lock nuts 451 Lubrication of center hearings.... 222 Lul>rication of drills 41 Lul>ricating machine centers 161 Lubricating, planer ways 280 Lubrication of milling centers 378 Lubrication of taps and dies 140 M Machine lK)lt8 450 Machinists' cold chisels 18 Machine cut flies 20 Machinists' hammers 17 Mandrel block 101 Mandrel centers 154 Mandrel centers, care of . . KU Mandrel presses 102 Mandrels 153 Mandrels, driving in bores 101 3Iandrels. expanding 154. 150 Mandrels, expansive, advantages of. 158 Mandrels for <'onical l>ores 1.58 Mandrels for large Iwres 1.5i> Mandrels, hardened and ground. . . . 155 Mandrels, influence of on sizes of bores l.'iO Mandrels, nut 159 Mandrels, solid 154 Mnndrels stub 100 Mandrels, taper of 150 Mandrels, with ends only hardened. . 155 Manufacturers* drilling machine. . . 406 Measuring machine. Pratt & Whit- ney 78 Measuring machine, Rogers- Bond. . 57 Measurini; machines. Sweets 79 Mechanlcnl equivalent of heat 542 Methods for testing stpiares 95 Method of lacing l>eltlug 495 Methods of lapping l^eiimg 494 Methods of producing screw tbreadb 129 Micrometer calipers, l>eam 70 Micrometer calipers, lK*nch 77 Micrometer calipers, for measuring screw threads 73 Micrometer calipers, inside 81 Micrometer calipers, large 74 Micrometer calipers, reauing of . . . . 71 ■'■Ji- ■ :iii:<< . .!. i- ! - use of 72 \HSIiuK arlM^i^ 348 Alinin^% ad\iialiiges for certain ilaajseH fjlT work over planing. . 312 Milling dliachmenr for planer. . . . 2i)3 Milling cutters, formti tif tH<»th 345 Milling t'Utt^r vibration. < iiujii^fi of. . 378 Milling (.'Utters, advantagi^ of small diametrr* of ,. 301-345 Milling cutters, angular 330-3.'{i» Milling cutters, axial ,'{30 Milling cutters, classes of 330 Milling cutters, inserted tooth.... 343 Milling cutters, formed 3:{0-33i>-341 Milling cutters, grinding of 345 Milling cutters, method of driving. 340 Milling cutters, nicked teeth 337 Milling cutters, radial 330 Milling cutters, straddle 337 Milling, direction of feed and rota- tion of cutter for 358 Milling, examples of .359-;m 1-303 .Milling head, universal 3*28 .Milling head, vertical spindle 328 Milling, in the lathe 260 Milling machine as a manufacturing tool 313 Milling machine, duplex 317 Milling machine feeds 321 Milling machine feeds, all gear.... 322 .Milling machine, plain 314 .Milling machine, slabbing 317 Milling machine, universal 313 Milling machine, vertical spindle.31>-319 Milling machines, importance of. . . 312 '^lli]^. ►•nil 338 Mill-, >i3H. tenter cut 3.38 ^|i*iihf>r lathe 189 Monkey wrenches 100 Movai)le racks 525 Movable hesd Itorlng twirs , 250 M II illiM- fur rempertni; , * ^ . , , MiKllijIi- ftittfrH, fiir boring. 253 MutHplc fluted drIllH and their uses. 107 ^lulciiili? uplndle drills .399 Multiple thread screws 128 Names of flies 22, 23 Necessity of l.elly in flies 29 Nut and washer gauges 85 Nut drivers 212 Nuts, machine 454 Nut locks 452 Object of tempering 440 odontograph. (irant's involute 470 Oil, flltering of 5*22 oil pump .334 Oil separator 522 Oil tulK» drills Ill Open side planer 27t» Ol>en side shaper 28R Overhanging arm supports 321 Oversize in taps 181 INUEX. Ii.a::;-r-. r^ri ■' -.t - •»1 K' ■an. .-,. INI i:. JL>. . i.. ;. *: !:• -a.'.» . *. 4. . u- aii:> ■"*. « .*• i' , K. ■atii* : •. .. ;;•» , K' -a Hi :■.«. •'i."i iC* ■aTii* r-. ". JT i;- ai.;-r-. '.».\ it' .iij- .*. • Ml U' a!i." • ,-'«. lA • |4I ' i:. ; ;:i> .^ .» ^.^ 7;; ■u- ■at:. ::Vl i'y -.iri: ;;j 1 •• i:-i r l:r»- ■•^l ii- -Ti; :.i:. J 7:» •i:. ■. i' . ■ ■!. - 74 j -.1 « 'l: ■ ^■. .:.- . ■' 'J i: . ■ ■' -:*._ '. . N .: ^--^ i; i: "■■■] !- ■'I- - 4'. ii-r- K:- , i_ ' — •'■ \ .: 1 '-_ _■•■. !: ■.- s •■■I ■•■ i: '.■! k. ."k J i: :■- :■.-• ■ i-: ■.•-....j ".'.• K . f - ■.'.•\-\ !;- ■»■•:. 1: .* f. r • 1. •.-::.::.: 4..: i; .-. ^.. 1." ;"4 INDEX. 551 'iPtMlnj? tiles for any class of work •Mi. :j4 olMiardcnliiK stwl olt'-oponlUK (lieH U'lleis' plnniM' tnblt? DtH 2»r»- St I sorowH Selling of larho tools S»^lHn« of rivfts S*»riln>; tool for taper turning S»»ttiuK iu> work for iKiriug Shaft. iH'arlnj; Shaft. <'o»i)linKs Shalt iiiK. aliiiiuK Simper, draw stroke Sliaper, 1110 va hie head ShaptM*. open shh* Shapers. eharaeterlstle parts Shapers, crank driven Shapers, rack driven Sheaves, rope Shi'Il reanii-rs Shrink lit, definition of Single cut flies SIal>hin^ cutti'r SItM'ves. drill Slide rest. Slotted link, for shnper Sloltini; attachment Shxtini; machine ShJttinj; machine work, example of. . So«'ket8. tlrili Sockets, special form «if drill Sockets for oil t»ilH> drills Sockets, frlctils Solid reamers Special form of drill sock«'ts Special tool for planing i-lrcular surfaces Speeds for milling <'Utters Sph«'rlcnl turning Sidierical socket iNiring Spi-ed of emery wheels Speed of hand lathi* Spindle ends sipiarlng off Spiral cutting nttacliment Spiral, cutting of a Spiral gears Spring for planer tools Spring Joint califM^rs Spiral gears, data for Spiral gears, elements of Spiral geared planer Spiral g»»arlng. prol»lem»* in Spiral gears, cut tin:; of Spirals, calculations for ili«» change g«'ars Spur gears Square. l>ox S«iuare corner lllini,' Squares. iMmililnatlon Squares, methods for toasting Squares, «tnndnrd steel Squares, thin sf'M'l S(p!aring off snindh* pnd<» Standard gauir^s Standard grail»'at<'d lin»*-inea»nip<>red w<»rk... Straight ed"i»s. cfi-t Iron Stralffht edges, steel Stay lK»lts Stay luylt taps , 4U LMH> i;{s 2i4 21»7 4."i;i 4()1 '2:ii 511 508 281) 280 288 282 28:{ 28a 110 2«J2 144 170 284 ;i:i4 •AU7 142 144 24S 147 14. -I 14ri l.TS ir.4 114 144 21MS 2til 4:n» 22:t ;{:;2 4»;7 471) 27 1; 4s:t .T.»4 :ir.4 4n7 i)7 'M or, 04 t)tt 22:t ."»0 .'»♦*, ;{07 0:1 04 tt? 445 OA 07 4A1 1S2 Slays, crown sheet 4tJ2 Siuys. diagimal i 4G1 Steady resi 225 Steel, air hardening tool 447 Stc»el. effect of carlsm in 44U Steel Imrdcniug 440 Steel, healing of 441 Steel, tpieuching of 44:i Steel, S4> 1 1 -hardening tool 447 Stock, keeping of 524 StopK. milling machim* table .'{75 Stud holts 451 Stud set 451 Supporting work not round 22t» Surface tals 5.'12 Tabl.» of speed of drills rt'Mi Table of standard dimensions of wrought iron steam, gas and wat»'r pl?M»s 7i'A4 Tal)le of lns Turnin;: crnnk pins Turning, exercise of bwlirinent In. . Tnrnlnir Irrei;nlnr outlines l!1'J- Turn in u: lony: work by use of bol- 141 14U 151 189 108 431 455 37ti 458 122 232 230 231 231 231 340 134 133 133 131 121» 132 131 135 132 130 135 445 107 445 447 444 443 440 445 179 08 107 339 424 282 291 227 29r» 30N 292 2!>3 292 404 .15 125 2 JO 24(5 24.-'> 2:{9 2:52 224 245 low Tiirninu' 'F'nrnin ofTset work sbaftinsr rnrniiiLr splierlcnl work . . Tnrniiiir tnper work Turret liorinir. example of T'nrrei cliiici.ini; litbe. antornntic Turret cbiK-kiiii: Intljes '^Piirret (Irllliui; in.Mcliinev; Turret faclii:: Turret mncirme rurret, on carrlnu .iple • .jM. rations Turret on slie 232 239 '2\:\ 20-220-2:V2 2."»7 192 192 4Ci:', 25 ♦; ^Hi\ 1SS -207 25S .19: Turret tools Turret work. exjn'M.] • of h«»nvy.... Twist drill cut tin;: in niilling ma- chine 'M\H Twist drill grinder i'A Twist drills 10.1 Twist drill, relieving of 3«y* Two classes of dies la., Two spindle lathe \k\ T'nited States standard of measurr .V. United Htates standard thread i::.-. I'niversal boring mills im3:» Cnlversal chucks i»i.*i Vniversal d rilling* tJiUleii 4u:t rnlversal ^r iii^llne muehlm* 42N Vnlversal Iii4ejtititf head ::2."i Tniversal mllUuK head, :r> I'nlversal mllllug machine :ii:{ rnlt of heat .'.4i' Unit of work .'»4j I'se of calipers «5. iJT Use of center head square 'JJl I'se of chalk and oil on flies 4."» Use of gauges ♦»! Use of graduated dials on feed screws :»;•_• Use of knee plate :?".'» I'se of micrometer calipers 72 I'se of oil tulje drills 24S I'se of scrapers 4S I'se of surface gauge •J21 I'se of test Indicator 92 Value of graduated machine dials.. 378 V blocks 303 V threads 125 Velocity ratio 400 Velocity ratio In elliptical gearing 40<> Vernier calipers, reading of 69 Vertical boring mills 204 Vertical milling, examples of 37o Vise, drilling 4o.h Vise jaws, soft 3.H Vise Jaws, spring 3S Vise. Jig drilling 4<»i» Vise Jigs 3S Vises, milling machine 327 Vises, planer 295 Vise, planer and sbaper. securing work in 3(M Vises, special jaws for 372 Vises, use of two in milling 371 \Vari)lng of articles In tempering . . Waste cans Water, data on Water, power re 102 .ainbow ^ Pa^cking L Imttjitors, '?!o €aual. Ed Riibc$t nurc. Don't Rai^e t^ Use Wire and Cloth to f»old Rainbow. Can't Blow it om. tHE COLOR OP RAINBOW PACKING IS RED Notice our trademark: of the word " Rainbow'* in a diatnond^ In Three Howfi of DiRtnondji in Black, extending througlMmt the entire length of ^ch and every roll of Rainbow Packing Itlannfactiirers of \ht famous Eclipse Sectional Rainbow Basket Peerless Piston and Ualve Rod Paclting Ifonest 3obn fvydraulic Rainbow Core Packing l^ercules Combination Arctic Jininionia Ring Packing Full and Complete Line of Fine Mechanical Rubber Goods kINCXUDING RUBBER HOSE FOR ALL PURPOSES - Send for 0\ir New CoLtBlogu^ p^\§hui and niantifacttired Excliul^lv by PEERLESS RUBBER MANUFACTURING CO. 1 6 Warren Street, NEW YORK We make a Specialty of Gang Drills' Tms K OUR FOUR SPINDLE 20 W CH GAHG DRILL It can be fumisbed in Two» Three or Famr Spfadlei with anr desirad amuigciiieist oC feed^ or m o«r Maan- ifcctiifcf^* style kiving^ seKopefmiins spmSke%, hMFgcr aIso fiAmsdied ui GsngSL « We boSd DtiBs from a is ia^ Frioioa Drhroi to ■ )i mA '^KUng Head; Sczw Cattm; La^es of 9 indk aad 11 iack S«n^ aad m wj* practical Wet Tool Gnader s«iws a s«xa indi WhecL R F. BARNES COMPANY. U. S A., RUBBER. Belting ^1846 Para** is out finest gfradc* It indicates exceptional quality in material of evcf 7 description, and gfoods bearing this brand can be depended upon to give the extreme of service both as to strength and dttrabillty. v< RUBBER. V HOSE n^ See that yi>yr Rubber Ho»e bears this trademark : We manufacture a complete line of Rubber Kosei for any and all purposes, WRITC FOK CATALOG ins New York Belting and Packing Ca«, Ltd^ 25 PARK PLACE, NEW YORK STAR.R.ETT v^TOOLSv TRADE k EMBODY the latest and most advanced ideas in practical to<:»l making. Tlicy are the standard for accuracy^ de- si^^n, finish and workmanship. Skilled mechanics prefer thcni ; live hardware dealers everyA'here sell them. Steel Rules, Squares, Micrometers, Bevels, Protractors, Steel Tapes, Plumb Bobs, Hack Saws, Levels, Calipers, Dividers, Center Testers. Surface Gauges, Screw Pitch Gauges, Speed Indicators, Cut Nippers, Steel Clamps, Wire Gauges, etc. • . • Complete IUvi«tT«^t«d CsLteJoifue fr««. B/>e L. S. STARRETT CO. ATHOU MASS., U. S. A. 123 Liberty Street 15 South CcLnA.! Street NEW YORK CHICAGO 1 GENERAL POWER COMPANY Specialists io Isolated Lrghtinj: 81=83 Fulton Street, New York TME OIL ELECTRIC PLANT USINC Secor Engines is the only lighting and power system guaranteeing all the elements essential to satisfactory, reliable and economical operation. This system is suitable lor all classes of [jropcrty all iver the world for lighting and power. UOHTINQ PLANTS CHARGEMO PLANTS SHOP ENGINES >ISTING PLANT5 PUnPlNQ ENGINES PORTABLE PLANTS COMPRESSING PLANTS 6$ Light Secor Plant TrarerK SHAPERSi PILLAR Md TRAVER5E Tile «,4iK«'.cwu ^b«per L4, THE BRADFORD MACHINE TOOL CX). CINCINNATI, OHia USA, M /^m*ir Acrvmrnmrn or Bradford Lathes and Lathe Attachments j ^ Printed MAttei* of Lathes from 14 to ^ 42-fnch Swingf Mailed any Address ^^ The Mew Britain Machine Co, t>m*i$in*rM a fid SmUtimrm mf Labor Saving Shop Conveniences Old style solid dies or taps often strip the thread especially when used on soft clin^ metal GEOMETRIC SELF - OPENING DIES and ADJUSTABLE COLLAPSING TAPS Will not strip the threads because there is no reverse motioo« Dies open up at end of cut and taps cotIapse« Write tw fttr juU pftrtiatlHrB aJniut thMC np- tractate toolib GEOMETRIC DRILL CO. (Westvllle Station! New H».ven» Conrt* ,SS^' If y0y want the best lathe and drill CHUCKS ^*^y WESTCOTT'S ytrtin (rest Grip. (iruttteatCapttcily ntul Huruhilltr. rhenpmid A*>ciiraic. WEi»Tt OTT C'H VVH, t"0«. Oneldrt. N. Y.. I . S, A Aflk lorrntak»KUO in EnKllt^li, Frencti. Hi>rtni6h Mriierman. FIRST PHIZB AT roiX'.MBlAN KX POSITION, 1 L MACHINISTS' FINE TOOLS Calipers » Squares, Rales, Micrometers* etc. Railway, Mill and Mining Supplies MAGHrHISTS' SUPPLY CO., 16-18 South Ctnal St., Chicago Scientific and Practical Books PU BUSHED BY NORMAN W. HENLEY & CO^ 132 Umaamu Si,, New York, U. S. A. 49~ Aay of these books will he sent prepaid on receipt of price to any addreis fn tite t world. j»- We will ficod FREK to any address !ii the world our loo-page Catalo^e of Scietitific and Practical OoDka. I AMkliiaoii. ferriiitiCM and Tlielr Prepaimtl4»ii« A €oiiipre1ieii«tve Trc^utliM? ou PerfutinTy : ConialmlDK cumiiltt*' cIlreLrloiis for making Oandki'RUlef rerfuooMJ. Stut^UInK SaJtss, Kat;lietsj, FximinatlBK PaatJJa ; PivpanUluna fur tbe Care of the Skin, the Mwuth, the llnlr ; rosmelk-s, llalr nye«. and ollu^r Tollft Artirles. 30u PutfL-!*, 3:! I Hunt rations. Svo, VUih $3.UU Rarr. Cateclilam an the Coiiibu«llou of Coal and th« Rrrvenflon or tunuket A ijra.:tirai treat bt' for aH interested 1q fuel ci^nomy and the aup- presHloii of Rmnke from Htatioiiary st*»ani boiler fnrnacea and from [ociu motive}*. HTt lllysr rat Ions. 1 Jmo. 340 Pages. Cloth • * * ..»,.,* ^1 *&i> HIackall. Alr-Brako c:ate«!liiiiiti : This book \» a oomiiietc siudj of tilt* airbrake e^jtilpment. including the laleat devkeh and inventluns us*'d. All fjarta of the elr brake, their trotibie^ and pefullrrltles. atnd a prartlcal way to tlnd and remedy Uiemi ■ are explained. Tbla iK>ok contains over I.IHH) (|uh>kiIoU(» with their an- ■ HWet'>f« and l.s oijmplet**ly Illustrated by Eii|:ravlng*i and Thrive t^rjje ^ Folding Hates of ttie \Ve5itin«bou»e Qukk-Acilon Automatic Brake, and ' alBo the 9'.»,'lnth Improved Air Tump. JtU Pn^^s. Ilundswimelv bound 111 Cloth. Fifteenth i'>JltUjii , . \ |1 .50 ^rlonMliaiir. ftaiv Flllii<; and ]IIanaK«iii«'tit of Saivus A itrartleal liaiitll»oiik oti lillni?, pummlng. j^wasing, hanimerfng and th€ hfh/Anti of band Kavvn, iIk- speeti. work and power lo run clrcnlar saws, etc,» etc. Fuily liiojitrHted. ilotb. |l.0O ^rtutiiliaw. ^« fill op Klnka'^t This i)ook is entirely different from any other on raachlne-fthop prac* tiee. It is not descriptive of unlvernal or common shop UMage. but Rhowa apeclai way« of doing work better. nn>re i beaply and more rwiddly than ■ uaual, as done In fifty or mare li^adlng ebops in i}tirojM> and America. ■ Some of Its over .jUU Iteroa and li*_*i* lilu.straUons are tontribut^'d directly m for Its pagea by eminent couHtructors ; the re«i have been gathered by the author in bin Thirty Years* Travel and Experience. Second Edition. Neariy -ItK) Vageri und 'S22 iriitstratloQU. Cloth ^2.6U GrlniKliaw. Engine Buniier^B €a tech lam s TeUlng Ijow to erect, adjurit and run the principal steam en^nes la the Tinit<*d Srates, I^eaeriblng the i>rinclpu| features of various speclaJ And well knckwn makea of engines^ Fourth Edition. Slid Pages. Fully iiitis- trated. Cloth . * , * f*J.UO GrlEtifttia\%'. Ktcam Cu^iiie C7aieclil«iii i A frericR of dlrtvt prtirtlcnl annwers to direct practical queatfons, mainly Intended for young engineer^} and for ejcamlnAthm queatlopa. Nearly 1. Qu^a- tiima with their Answers. Twentysetotid t:dltlon, great iv enlarged. Nearlv 450 PageH. over _MK> lilustratlong. and 12 Large Folding Platea. Bouut^ In MariMm Cloth 12.00 niaeox* Gas, Gaaolfiie and Oil Enfflneat F'uii of geni^ral Information alHUit the new and poptilar motive power, ■ tti* *nronorov and mu^v of mmia>;em»>n'. Also chapters on Iloraelesn Ve- ■ hlcleH. FJectrk- Llgbthig, Marine Pro|>ul«ton. etc. Special chapters on ■ Theory of the tJa.« and r.a,Hoilne Engine. Utlllzntioa of Heat and Efflciency ■ of Gas Kngiiies. rieiard**d ronibTjsrion and Wall I'ooling. Causew of Lo»!* ■ flfTd Inefl\clencv In Exploslvf« Motors. Econotny of the Gon Engine for ■ Electric Lighting. The Material of Powpr In Explosive EngineK. Car- ■ hureters. Cylinder f'ttra*'Ity, Mutflers, tjovernors^ Ign iters and Kx* I NORMAN \V. IIKNl.EY & Co. N I'L* Hl-lCATir j.VS. i»|o«|«>rs, ('.\llnilfi- Lnlirlratnrs. Tlio Mfnsiiri'iii<>ni ^f I'i«w»T. Tli»' Iii(li< aror mill ii^ \\<>ik. Ih-ai i-:ilirli-iiilriiiN iHi *iun, iia****l\xf siini ifW IIiJuiiM's iiiiil tlH'lr ii(ljiiiirf> slut I- I.sT.'i. *'\r, 41J I'lii:'—. LiiiK'' '»'!nvii. Iliii^iiiiii-il wiih ::ij lltiii(Nd and i:iil!ii-i:i'<|. Km ki;uii |iII<*hII«»ii»i <;i\i!m ih- III! rniiMl.\ii;iiiiir<«, i •■ni]in-'^<>iiiii. i inii^iiii'-sifii. f.\iinri«'i"Ti. hijiI iiw.,,i |'ii|- |iti\\iT iitiiiiii'xi'H ill niiniiii: iiml t'liu'iiifiM'lii;^ work: j luiiini-. -h«»|i iMi»l-.. all' ]il:isr^ fur •li'Uiiliit; ami piiintiii;:. air lirt.-. piiui[i- IMU III' war. -I. .1. hjv ;iiii| nils: :i>iaih>ii ami |>urilii-aiiiiij •>[ wali-r ^iiiiply. I'iiilwa.v pM-|>iiUh>'i. |iii> innai h iiiIh* iiaii.'siiilsNliiii. i->'fi-tK*'i iiTi<>ri iiriil Miiiiii-r appill Mil rv III whiih i tiiii|iri-vsi i| air Is a iii'>-t rurivi-nit'iii ari') i-i ••ii-'iiii :il \>lii<|i< I'lir wiiik Willi lalili-x: nf •-iMii|ir<"»->i<>ri. •■vpanoi.iu ;\i\,\ ih« |ili>s|, :ii |.|ii|ii>i |ii-K i.f ah*. I.aiui- in'ravn. mmi rap'>. liiHr )lli|.- 1 1 ;ii inii-. I'l ii I- *."i,-.» lll«««»\. Il«»r««>i«*«« %'4*iil«'i«'M4 AutoniohlIrM an«l nfttor f*>rh**« Op«-r^ ai«' si«*uiii. If >dro-<'url>uii, I'lirrirlr aiiid Pufiiliiatli* .V|f»tun: riw TM.iU." I'l- aiiij iii.i!!;»j. Mi'iii Ml" Vnt I'li.t.ii • \flii. Ii-! i-f all k!t;i!- ;i:i- ti»;r •! (: aS Mi;iiTis ; )'.!••■ li^i .f . |,i- Air«-iii«iiiili' ainl \I"t r N|.>!ii:':i "lilt I, \ii;|i ■'.. , .i,M!.-.~i* i« \\.':\ II- it ii- nf jiari-n'o i"-':--! -i:i. I is.'.i; .-n iIh- A's-.-in-!.::.- |{ii|iin:-\ NiLn-iiiii « Laii'i-r-. I.ar^- ■*»\". ;.i»i !.:■!-!.' 1 1 .1.-. |i,n r.i.. . ♦:..:■! *;i.w ]|Uf«»\. ^«'<-liHiilral *lt»\4>iii4'iii«, Po«vor»« I>4*vi«T« and Appllanccti i'l.i- .«. ." ]'. .\ \^.' h . :. I .-•■ r ■■ \I. . !i.i!.i. ^. M-. l::Mi-;t: M.-\ ■rii-n*-'. 1 ». » :. . ^ ..l!,| A;-:. IM. ■ H. .: ... .. • l... ^^l,.l;,. :;ilj^.-..t Th- pJ.I- rii -.ii i\^.•\ "i\-\ w" ■ . .1 r. :- . : M. I.riiii. - hf. ■•i|f .•!-. I'.UiZi^ r-. I»:.i _'■•-!"■:• .i: il ;i ' ■'. - ;•-.•.* .1 !■, ;';:\ w .n jii :;i- • I.:| II I- •*. I^irtf»: *»\ . «'\ .; Ji'ii |-|_. , ■. !'. ^: , .., . M.i.l I ; ..• ::'i..!,,. \\i;U I »•— i'ip- i'\ V'\- \ ■! ' «3.W lli\ontiir«* Manual: llii«« im ^;ik4* n Pnlciit l*a> : 1' ^ - • ..:..■■. . _ ■•■■■•,■.;> rr".- '1!;^ -^.'-'.r i:i- \ ■ ■ ■ - "• > ■■■'■;■;»■■■"•"-■:■ -.vTA 1 r.» Taj--. N- u !.■.-. • . ?1 •••I Kraiik«. I.iut-ar !'• r«i»i«llic S<>||« Tail:: III. . . ! . s_.:j. 1 • ^ :iii. H.I I. 1 % 1 .lit <« : I 111 ir II :«!• r^ . I ri\ • iiil'in an«l « a If illation: > 1 . U*} |*.i :.'.'. A %« • .! I « I ;..Mi- « > I: «I ri.. Ii* II : lit^.ii*. 1- KI.-.i-i A^ I i-.iii •— «* ^ii>1 ^i 111- ni«* « hart and Hand U ^ :h- H •Il i I !«' I *' •: n . H' ■ ii; I .c ; » . «1.W h: ••:- U ** H. I % t -1 ij n : Sl.C* *' -t^ . (r^< > -ff< • V NORMAN W. HENLEY & CO/s PUBLICATIONS. Sloane. Blectrle Toy IHaklnS) Djnamo Balldlnc *nd Electric Motor Construction t This work treats of the maklni; at home of Electrical Toys, Electrical Apparatus. Motors. Dynamos and Instruments in general, and is de- Higned to bring within the reach of young and old the manufacture of g«Miulne and u»ofnl electrical appliancen. Third Edition. Fully Illus- trated. 140 rages. Cloth fl.UO Sloanc. Rabber Hand Stamps and the Alanlpalatlon of India Rubbers A practical treatise on the manufacture of all kinds of Rubber ar- ticles. 146 rages. Second tklltion. Cloth ; |1 .00 Sloane, Liquid Air and tbe Liquefaction of Gases i Containing the full the<>rv of the subject, and giving the entire historj of liquefaction «>f gases, from the earliest times to the present. It KhowH how liquid air like water is carried hundreds of miles and la handled in open buckets. It tells what may be expected from it in the near future. 36r> Tages. with many Illustrations. Handsomely bound in Kuckram. Second Edition ^.Ml Sloane. Standard Electrical Dictionary: A practical handbook of reference, containing definitions of about .'),(M)0 distinct words, terms and phrases. An entirely New Edition, brought up to date and greatly enlarged. Conijiiete, Concise. Con- venient. «>8li rages, 'AU'.i Illust rations. Handsomely Inmnd in Cloth. 8vo W.Ot Usher, The ITIodern ITlachlnlstl A practical treatise eml)raclng the most approved methods of modern machine-shop i)ra«tice. anortant cases, also the Transmission ol Power by Shafting with formulas and examples is included. This lK>ok Is strictly up-to-date and is the most < hi Illustrations 14.00 Wood worth. DIvh. Their <'onfttruction and Tse for the IHodeni WorlKlne of Sheet IfletalH: A treat Ne upon the designing. <<»nstructing and use of tools, fix- tures and wer j)ress. for thi' cheap and rapid production of sheet metal parts and articles, roiiiprlsing fundamental Illustrations . . ^.00 H'oodworCli. Hardcnluffy TempeHns, AnnealiuK and Forslnc •< Steel : A new l)ook containing spe<«ial directions for the successful hardening and tempering of all steel tools. Milling cutters, taps, thread dies, ream- ers, both solid and shell, hollow mills, punches and dies and all kinds of sheet-metal working tools, shear blades, saws, line cutlery, and metal- cutting tools of all des