What is the difference between VDI and BMT driven tool holders?

VDI is a cylindrical shank interface standardised in DIN 69880, sized by shank diameter (VDI16 to VDI60). BMT (Base Mount Turret) is a flange-mounted interface defined by the machine builder, sized by the bolt-circle pattern (BMT45 to BMT85). VDI holders locate on a cylindrical shank with a serrated clamping face; BMT holders bolt directly to the turret face, which gives higher rigidity. Both are open machine-side standards, so switching tooling supplier does not require changing the turret.

How do I know which turret interface my lathe uses?

The interface is set by the machine builder and turret model. Mongtec publishes the declared turret interface for over 350 lathe models; browse by brand and model, or send the machine make, model and turret type and Mongtec engineering will confirm.

Mongtec Driven (Live) Tool Holders — by Turret Interface

Mongtec Precision, a Taiwanese tooling brand headquartered in Taichung, Taiwan, publishes 228 driven tool holder article numbers across 7 VDI and 5 BMT turret interface sizes. Each article number is listed with its collet, gear ratio, maximum speed and torque rating.

Mongtec AX axial driven tool holder with ER collet output

Driven tool holder types

The interface decides what bolts to your turret. The type decides what the tool can actually do. Mongtec publishes these families across BMT40–BMT85:

Machine-specific turret mountings

Some machine builders use their own bolt pattern rather than a standard BMT size. A standard BMT holder will not mount on these, so they need a dedicated family:

Index by turret interface

Interface	Standard	Article numbers	Lathe models on this site	Browse
VDI16	VDI (DIN 69880)	8	0	VDI16 article numbers
VDI20	VDI (DIN 69880)	9	0	VDI20 article numbers
VDI25	VDI (DIN 69880)	8	1	VDI25 article numbers
VDI30	VDI (DIN 69880)	62	8	VDI30 article numbers
VDI40	VDI (DIN 69880)	75	22	VDI40 article numbers
VDI50	VDI (DIN 69880)	16	1	VDI50 article numbers
VDI60	VDI (DIN 69880)	3	1	VDI60 article numbers
BMT45	BMT (machine-builder spec)	7	8	BMT45 article numbers
BMT55	BMT (machine-builder spec)	19	14	BMT55 article numbers
BMT65	BMT (machine-builder spec)	11	25	BMT65 article numbers
BMT75	BMT (machine-builder spec)	6	1	BMT75 article numbers
BMT85	BMT (machine-builder spec)	4	0	BMT85 article numbers

Article codes are machine-builder specific. The codes below are the published range for this turret interface. Mounting and drive-coupling details differ between machine builders even within the same nominal interface size, so Mongtec engineering confirms the correct article code, clearance and coupling for your specific machine at RFQ.

Mongtec driven tool holders

Driven (live) tool holders from the Mongtec range — axial and radial types with ER collet chucks, for BMT and VDI turret interfaces. Photographs of actual production units.

Mongtec BMT driven (live) tool holder with ER collet chuck and internal coolant port

Mongtec VDI driven tool holder for DIN 69880 turret, ER16 collet

Mongtec BMT60 driven tool holder, ER32 collet, engraved speed and torque rating

Mongtec BMT driven tool holder with ER25 collet chuck

Range of Mongtec compact driven tool holders for CNC lathe turrets

Group of Mongtec BMT driven tool holders showing drive coupling and collet ends

Mongtec driven tool holder, model M3508, with output spindle and ER collet

Mongtec BMT axial driven tool holder with ER collet nut, front view

VDI or BMT — what is the difference?

VDI (per DIN 69880) is a cylindrical-shank interface. The holder locates on a ground shank and is pulled against a serrated face by a drawbar or clamping screw. Sizes are named after the shank diameter in millimetres: VDI16, VDI20, VDI25, VDI30, VDI40, VDI50, VDI60. It is the common interface on European-built turrets and on many disc-type turrets.

BMT (Base Mount Turret) is a flange interface. The holder bolts directly onto the turret face on a defined bolt-circle pattern, which gives higher rigidity and better repeatability under heavy milling loads. Sizes are named after the mounting pattern: BMT45, BMT55, BMT65, BMT75, BMT85. The pattern is defined by the machine builder rather than by a single public standard, so the same BMT size from different builders can differ in detail.

Both are open machine-side interfaces. Changing tooling supplier does not require any modification to the turret — which is why a Mongtec holder can replace an OEM or European-brand holder of the same interface.

Angle heads for machining centres

Mongtec publishes 137 right-angle machining head models — BT30, BT40 and BT50 spindle interfaces, with ER collet, DC chuck, FMB face-mill arbor and BT40 tool-holder outputs.

All angle head models (137) → · Angle heads for machining centres →

Driven and static tool holder types

Twelve published body types. The type decides the holder family before collet size, ratio or torque; the turret interface is confirmed separately at enquiry.