BMT is not an ISO or DIN standard. It is an industry de-facto standard, so the same nominal size — BMT55, BMT60, BMT65 — can mean different bolt circles on machines from different builders. Several builders skip the nominal size entirely and use their own bolt-hole pattern. The table below lists 38 turret bolt patterns found in published tooling catalogues and the machines that use them.
Mongtec supplies driven and static holders for all of these, including the machine-specific ones. Send the machine model and we confirm the fit before quoting →
Most turret makers build the five common BMT sizes to the same pattern. Check these first; if your turret does not match, look for it in the builder table below.
| Size | Centre bore | Bolt spacing | Mounting screws | Key slot width |
|---|---|---|---|---|
| BMT45 | ø45 mm | 58×58 mm | 4 × M8 | 15 mm |
| BMT55 | ø55 mm | 64×64 mm | 4 × M10 | 15 mm |
| BMT65 | ø65 mm | 70×73 mm | 4 × M12 | 18 mm |
| BMT75 | ø75 mm | 90×90 mm | 4 × M12 | 25 mm |
| BMT85 | ø85 mm | 100×100 mm | 4 × M12 | 25 mm |
Common values for each size. Builder-specific turrets differ — confirm against the turret drawing. How to measure your turret and the patterns most often confused with these: BMT turret dimensions guide.
| Bolt pattern | Machine builder | Example machines |
|---|---|---|
| 30×64 mm | Mori Seiki / DMG MORI | ZL150 |
| 35×76 mm | Mori Seiki / DMG MORI | ZL200 |
| 40×55 mm | Nakamura-Tome | WT100, GTS150, GTS100 |
| 40×55 mm | Muratec | MT100 |
| 44×50 mm | Wasino | A12 |
| 44×60 mm | Takahashi | — |
| 50×50 mm | Biglia | B436Y2, B436 |
| 50×60 mm | Nakamura-Tome | WT150, AS200, WY250, WT100 |
| 52×56 mm | Miyano | — |
| 52×100 mm | Goodway | GS400M |
| 52×100 mm | Mori Seiki / DMG MORI | SL400, UT400 |
| 54×54 mm | Miyano | — |
| 54×70 mm | Muratec | — |
| 55×60 mm | Femco | HL25DM |
| 55×60 mm | EMCO | HL25DM |
| 56×68 mm | Miyano | — |
| 57×54 mm | Wasino | A12 |
| 58×58 mm | Takamaz (same spacing as standard BMT45) | XY120 |
| 58×60 mm | Takamaz | XL100 |
| 60×60 mm | Takisawa | LA150 |
| 60×70 mm | Takamaz | X10, XY12 |
| 60×75 mm | Miyano | ABX51, ABX51SYY |
| 62×70 mm | Mori Seiki / DMG MORI | NZ1500, NZ2000 |
| 63×65 mm | Biglia | B465 |
| 64×64 mm | Standard BMT55 — Victor, Doosan, Hyundai WIA and others | VTurn A16/A20, Lynx 2600 Y/SY, HD2200 |
| 65×73 mm | Okuma | LB3000EX, LB3000 |
| 65×80 mm | Okuma | LT2000EX, LT2000EX16 |
| 68×110 mm | Mazak | QTS200M |
| 69×71 mm | Nakamura-Tome | WT300, WY250L |
| 70×70 mm | Takisawa | EX308, NEX108, NEX108M, FX800 |
| 70×73 mm | Standard BMT65 — Doosan / DN Solutions | Puma 3100, Puma GT3100, Puma VT450 |
| 70×73 mm | Standard BMT65 — Victor | VTurn A26, VTurn S26 |
| 70×95 mm | Takisawa | — |
| 73×78 mm | Okuma | LT2000EX |
| 78×80 mm | Okuma | LB4000EX |
| 84×94 mm | Mori Seiki / DMG MORI | NL1500, NL1500Y |
| 100×100 mm | Standard BMT85 — Victor, Doosan / DN Solutions | VTurn-V1000, Puma 600/700/800 |
| 125×90 mm | Ikegai | — |
Compiled from published tooling catalogues. A bolt pattern is a physical property of the machine turret, not a proprietary design. Always confirm against the turret drawing for your specific machine and turret version — the same machine model is sometimes shipped with two different turrets.
A BMT turret mounts the holder directly to the turret face with four screws and locates it on keys or a spigot. Two things define the mounting: the bolt pattern (the centre distance between the mounting holes, in mm) and the drive coupling that transmits rotation to the tool. A holder fits only when both match.
Where a builder also publishes a nominal BMT size, use it as a first filter and the bolt pattern as the confirmation. Where no nominal size is published — common on Nakamura-Tome, Okuma, Miyano and Takisawa — the bolt pattern is the only reliable identifier.
BMT45 58×58 mm with M8 screws, BMT55 64×64 mm with M10, BMT65 70×73 mm with M12, BMT75 90×90 mm with M12 and BMT85 100×100 mm with M12. Builder-specific patterns differ, so confirm against the turret drawing.
No. BMT (Base Mounted Turret) is an industry de-facto standard. It is not published by ISO and it is not published by DIN. VDI, by contrast, is standardised in DIN 69880. This is why two turrets both described as BMT65 can have different bolt circles, key positions and drive couplings.
Because the bolt pattern is what physically decides whether a holder mounts. A nominal size such as BMT60 tells you roughly how big the turret disc is; the bolt pattern — for example 65×73 mm on an Okuma LB3000 EX — tells you where the four screws actually go. Ordering by nominal size alone is the most common cause of a holder that will not bolt on.
Measure the centre distance between the mounting holes on the turret face, or read it from the turret drawing in the machine manual. Send Mongtec the machine model and a photograph of the turret face and engineering confirms it against the drawing. That check is free and takes one email.
Yes. Machine-specific bolt patterns are supplied to order alongside the standard BMT and VDI ranges, including Mazak 68×110 (S68), Goodway D63, Tsugami TS65 and Takisawa TA60. Describe the operation and the machine.
The full dimensioned drawing is supplied by email once an enquiry is open, so that it matches your actual machine and turret configuration.
All driven tool holder types and turret interfaces · Published article numbers · Live tooling by machine model · Selection guide