Okamoto
Okamoto Corporation of Vernon Hills, Illinois is the US subsidiary of Japan’s Okamoto Machine Tool Works — the name US shops know first for ACC surface grinders and IGM internal grinders.
Independence note. Grinding Advisor is not affiliated with Okamoto. This page summarizes public information to help buyers evaluate the line.
Fast facts
| Headquarters | Okamoto Machine Tool Works, Ltd., Yokohama, Japan |
|---|---|
| US presence | Okamoto Corporation, 370 Corporate Woods Pkwy, Vernon Hills, IL, plus branch offices |
| Machine types | Surface, internal, cylindrical and combined ID/OD grinders |
| Official site | okamotocorp.com |
The company
Okamoto Corporation (Vernon Hills, IL) is the US subsidiary of Okamoto Machine Tool Works of Yokohama, Japan, established in 1972. US shops know the name mainly for ACC-series surface grinders and IGM internal grinders; the line also includes cylindrical (OGM) and combined ID/OD machines.
What they build
- Surface grinding — ACC / ACC-DX series
- Internal (ID) grinding — IGM series
- Cylindrical grinding — OGM series
US presence & contact route
Okamoto Corporation in Vernon Hills, IL is the US route for new machines, parts and service, with branch offices in Santa Fe Springs, CA, Louisville, KY and Windsor, CT.
What buyers ask
- ACC generations run from hydraulic to full CNC — which generation fits our surface work and our budget?
- IGM internal: chucking or between-centers for our parts?
- Where do I get a manual and parts for an older ACC? (Our manual archive is a start — the builder is the authority.)
- What’s the US stock position on wear parts for this model?
The used market, plainly
ACC surface grinders are everywhere in US shops, which makes the used market active and the manual hunt constant. On a used ACC, generation is everything: a hydraulic machine and a CNC machine with the same badge are different purchases.
Grinding Advisor is an independent advisory service. It is not affiliated with, endorsed by, or a dealer or representative of any manufacturer listed here. Company and product names are trademarks of their respective owners and are used only to identify those companies and their products. Directory information comes from public sources and was last checked October 2026 — confirm specifications and contact details with the manufacturer.