BMT Speed Increaser (Speeder) Driven Tool Holders | Mongtec

Small-diameter drilling and milling at surface speeds the turret drive cannot reach. Published for BMT40, BMT45, BMT55, BMT65, BMT75, BMT85. Mongtec Precision is a Taiwanese brand, designed and engineered in Taichung, Taiwan.

What it does

A speeder holder steps the turret drive up through an internal gear set, so a spindle rated at 6,000 rpm delivers 12,000 rpm at the cutter. The reason to want that is simple: surface speed is diameter × rpm. A 3 mm carbide drill or a small end mill needs high rpm to reach the cutting speed the carbide grade was designed for. Run it at turret speed and you are cutting too slowly — the edge rubs instead of cuts, tool life collapses and the finish suffers.

The trade is torque: 1:2 gearing halves it. These are finishing and small-diameter tools, not roughers.

When you need one

Published specification

Turret size	Gear ratio	Max speed	Max output torque
BMT40	i=1:2	12,000 rpm	40 N·m
BMT45	i=1:2	12,000 rpm	40 N·m
BMT55	i=1:2	12,000 rpm	40 N·m
BMT65	i=1:2	12,000 rpm	40 N·m
BMT75	i=1:2	12,000 rpm	40 N·m
BMT85	i=1:2	12,000 rpm	40 N·m

Source: Mongtec BMT Driven Tools PRO catalogue, Ver 2026.07. Figures are the published range for the family. Full PDF catalogues are available from the Mongtec website.

The article number comes from the drawing, not the label. BMT is an industry de-facto standard — it is not published by ISO or DIN — so bolt circle, key position and drive coupling can differ between machine builders at the same nominal size. Send the machine model and a photograph of the turret face; Mongtec engineering checks it against the actual turret drawing before quoting. That check is free and takes one email.

Custom builds

Mongtec builds this family to order as well as to catalogue. Special angles, extended reach, high-pressure internal coolant, non-standard collet or arbor mountings and machine-specific bolt patterns are all within scope. If what you need is not a catalogue item, describe the operation and the machine — that is usually enough for engineering to say whether it can be built and roughly what it involves.

Frequently asked

What sizes is this family available in?

Published for BMT40, BMT45, BMT55, BMT65, BMT75, BMT85. The article number for your machine is confirmed against the actual turret drawing at RFQ.

Can it be built as a special?

Yes. Special angles, extended reach, high-pressure internal coolant and non-standard collet or arbor mountings are built to order. Describe the operation and the machine and engineering will say what is possible.

Will it fit my turret?

BMT is an industry de-facto standard, not published by ISO or DIN, so the same nominal size can differ between machine builders. Send the machine model and a photograph of the turret face; the check against the actual drawing is free.

Are dimensioned drawings published here?

No. Mongtec supplies the full dimensioned drawing by email once an enquiry is open, matched to your machine and turret configuration.