Used Okamoto Machines We Buy

Who Builds Okamoto Grinders

Okamoto grinders are built by Okamoto Machine Tool Works, Ltd., a Japanese company whose head office has been at its Annaka factory in Gunma Prefecture since 2012. Kakusaburou Okamoto founded the business in November 1926 as Okamoto Specialized Machine Tool Manufacturing, and it was incorporated in June 1935 under the Okamoto Machine Tool Works name; Okamoto counts its establishment from 1935. Its first landmark was a gear grinder: in 1930 it developed Japan's first gear grinding machine, the ASG-2, and Okamoto still says its history is built on gear grinding technology.

Today Okamoto makes grinding machines and semiconductor-related equipment. Its US arm is Okamoto Corporation, which Okamoto set up in Chicago in 1972 as a sales company. Okamoto Corporation now lists its headquarters in Vernon Hills, Illinois, with offices in Placentia, California, and Windsor, Connecticut.

Okamoto Corporation Is Not Okamoto USA

Search for Okamoto USA and most results are about Okamoto Industries, Inc., a different Japanese company. Its own plant list shows it makes plastic films, wallpaper, condoms and gloves, and its American plant in Sandusky, Ohio, makes materials for car interiors; no grinder appears anywhere on that list. The grinder maker's American company is Okamoto Corporation, which Okamoto Machine Tool Works counts as a consolidated subsidiary. If a buyer or a search result mixes the two up, the grinder on your floor belongs to the second one.

Where Okamoto Grinders Are Built

Okamoto names three factories with ISO 9001 certification: Annaka in Japan, and its plants in Thailand and Singapore. Annaka began operating in 1982 and earned ISO 9001 in 2004. Okamoto (Singapore) Pte, Ltd., set up in 1973, was the first local subsidiary to manufacture machine tools in Singapore, and in 1994 it became the first plant in the Asian machine tool industry to earn ISO 9002. Okamoto (Thai) Co., Ltd. followed in 1987; a new casting plant there in 2006 took the combined capacity of its old and new foundries to 1,800 tons a month. Okamoto also lists Okamoto Machinery (Changzhou) in China as a production place.

So a used Okamoto on a US floor may have been built in Japan, Singapore or Thailand. We scope it the same way whichever plant it came from: family, control, way wear and whether it still holds size.

When Okamoto Introduced Its Grinder Families

The grinder families on Okamoto's own company history, with the year Okamoto gives for each. Older plates under this hub (PSG, IGM, OGM, PRG, PFG) date from these lines:

From Okamoto's own company history, which runs to 2024; the table keeps the grinder families and leaves out the company's semiconductor equipment.

Okamoto's Grinder Lines and Controls

Okamoto Corporation's US catalog covers surface, form, rotary, internal, cylindrical and universal grinding. Surface grinders come in saddle, column and double-column builds; rotary surface grinders run as the PRG and VRG-DX families; internal grinders carry the IGM name, cylindrical grinders OGM and universal grinders UGM. Okamoto sells each series with one of four control levels: manual, automatic, MDI or CNC, and the table below lists which is which.

Okamoto has been building CNC grinders a long time. In 1968 it developed what it calls the world's first CNC surface and form grinding machine, the NFG-5, and in 2010 it developed its iQ software to turn surface grinding know-how into software, then built machines that carry it. The control level is one of the first things we ask about, because a manual Linear and a CNC iQ column machine are different offers even at the same table size.

Okamoto's US Grinder List by Type

Okamoto Corporation's current US grinder list, grouped the way the list groups it, with the control level Okamoto gives for each series:

From Okamoto Corporation's Grinding Machines page, which says specifications are subject to change. Families that have left the list, such as PSG-DX and PFG, are in the history table above.

What the 577 Okamoto Listings Actually Hold

This hub carries 577 Okamoto listings and one brand only. The category split is complete and it is lopsided: CNC Grinding Machines 562, CNC Miscellaneous Machines 7, CNC Horizontal Machining Centers (HMC) 3, CNC Gear Machinery 3, Metal Cutting 1, CNC Horizontal Boring Mills 1. That puts 97.4 percent of the hub in one category and leaves 15 listings, 2.6 percent, spread across the other five. The concentration is the story here, not a gap. Measured against our CNC grinding hub, Okamoto is the most common builder across our CNC grinding listings, 562 of 2,198, ahead of Chevalier at 523 and Tos at 355, rank 1 of the 32 brands in that category. Depth does not mean repetition, either. Those 577 listings carry 517 distinct model designations, so close to nine entries in ten are a different machine string from the one before. Almost nothing in this book repeats from one listing to the next.

ACC, PSG and OGM: the Families That Carry This Hub

By leading token, ACC is the largest family at 210 listings, 36.4 percent of the hub, all 210 filing under CNC Grinding Machines. PSG follows at 78 listings, then OGM at 45, LINEAR at 25, IGM at 21, PFG at 17 and ACCUGAR at 14, each filing entirely into CNC Grinding Machines. Below them, 618 at 10 and 1632N at 7, the only family in this list that does not file entirely into grinding, 6 grinding and 1 metal cutting, then 612 at 5, ACC16 at 5, ACC12 at 4, 820A at 4, 1624N at 3, 820N at 3 and OGM12 at 3. Families of two or more account for 512 of the 577, so the remaining 65 are one-offs. The strings a searcher types turn up here verbatim: ACC-1632DX, ACC-16-32DX, ACC-12-24DX, ACC-12-24ST, ACC-124DX, ACC-618DX3, ACC-820-DX, ACC-820-DXNCP, ACC-20-36-DX, PSG-84, PSG-158DXNC, PSG-308, IGM-2MB, OGM-12, ACCUGAR-124N, 1632N and GC-40. ACC16, ACC12 and ACCUGAR are separate roll-up keys, not part of the ACC 210.

Cast, Scraped and Assembled In-House

Okamoto casts the bases of its machines itself. Its production page describes one chain inside the group, from wooden pattern design through casting, component machining, painting and final assembly, and says every one of its manufacturing sites, in Japan and abroad, has its own processing factory. Sliding surfaces are still scraped by hand, a technique Okamoto calls kissage, and Annaka has constant-temperature rooms and clean rooms for ultra-precision grinders.

That is why way wear is near the top of our questions on a used Okamoto. Tell us whether the ways have been reground or rescraped since the machine left the factory, and whether it still holds finish across the full table.

What Determines the Offer on a Used Okamoto Grinder

With 562 of 577 listings here filing as grinders, the scoping call is a grinder call. Jason Puuri asks about the wheel spindle first: hours if anyone tracked them, how it sounds and pulls, and what has been done to it. Then whether the machine still holds size and finish on a test grind, because that one answer settles more than a spec sheet. After that, way and slide wear, control generation and whether parts and service for it are still reachable, chuck and wheel packs on hand, dressers, coolant and filtration, and any loader or in-process gauging that comes with it. None of it runs through a formula. Jason weighs those details himself against what the machine needs to go back to work. Only 227 of 577 listings record a build year, and those run 1977 to 2026, so a late-1970s machine and a current-year machine are different conversations.

The 15 Okamoto Listings That Are Not Grinders

Take 562 grinding listings out of 577 and 15 are left. Named, because the split is complete: CNC Miscellaneous Machines 7, CNC Horizontal Machining Centers (HMC) 3, CNC Gear Machinery 3, Metal Cutting 1, CNC Horizontal Boring Mills 1. Part of that is traceable in the family roll-up. The HMC key splits 2 into horizontal machining centers and 1 into horizontal boring mills, and the 1632N key puts 1 of its 7 into metal cutting. The catalog gives us a category for those and nothing else, so we are not going to characterize them or guess at model names. If what you have is an Okamoto that is not a grinder, it does not need to match anything on this page. Send the full designation off the plate and what it is set up to do, and it gets scoped like a grinder. Our horizontal machining center and gear machinery hubs cover those categories broadly.

Have This Ready Before You Call

The most useful thing you can send is the full designation exactly as it reads off the data plate, not a partial. Inside this hub alone, ACC-1632DX, ACC-16-32DX, ACC-16.32DX, ACC-12-24DX, ACC-124DX and ACC-12-24ST are separate catalog strings sharing tokens, and ACC-618DX3 and ACC-618-DX3 differ by a single hyphen. With 517 distinct designations across 577 listings, the exact string is what places a machine. Serial number next, then control type and generation, build year, wheel spindle hours if they were ever tracked, the chuck and wheel packs on hand, whether it still holds size and finish, and whether it is running now or has been sitting since a job ended. On the year: only 227 of the 577 listings in this hub record one, which is why we ask instead of looking it up. If the plate is painted over, the serial and a clear photo still give us something to work from.

Selling an Okamoto Outright Instead of Listing It

Machine Tool Exchange purchases the machine. No consignment, no broker in the middle, and no requirement to buy something new the way a trade-in works. You are not waiting on a buyer to appear. One ACC or a whole grinding department comes out on a single quote and a single pickup schedule, which matters when a cell has to clear by a date. Machines idle since a job ended, pulled during a changeover, or parked while somebody decides about a spindle all still get scoped. What speeds the close is proof the company owns the equipment outright rather than on a lease or finance agreement. Grinders are what we chase hardest, and we buy well past this one badge: Chevalier, Tos, Blanchard, Heald and Landis grinders, and across the wider shop Mazak, Haas, Okuma, Doosan, DMG MORI and Makino. This hub itself is Okamoto only.

Okamoto Service and Dealers, or Selling Outright

Okamoto Corporation keeps separate sales, service and parts lines at its Vernon Hills headquarters, and its dealer finder covers the United States, Puerto Rico, Canada, Mexico, and Central and South America. Okamoto says it posts service engineers around the world for regular inspections and machine maintenance after delivery. That network is the right call for an Okamoto you plan to keep grinding. For one you want off the floor, we buy it outright, and a service report or a record of spindle work is worth sending with the details.