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Mongtec BT shrink fit chucks — through coolant

Q: What run-out do Mongtec BT shrink fit chucks hold?

Run-out is ≤ 0.003 mm at 3×D and the chucks are balanced to G2.5 at 25,000 rpm, which is what makes shrink fit the first choice for high-speed and deep-cavity work.

Q: Do I need a special machine to fit these?

Yes — a shrink fit induction unit heats the bore to release and clamp the tool. Mongtec supplies the machines as well as the holders; ask for the shrink fit machine range with your enquiry.

63 article numbers on the BT (MAS 403 BT, 7/24 taper) shank, bore Ø3–32 mm, 4.5° clamping taper, with through-coolant supply. Run-out ≤ 0.003 mm, balanced G2.5 / 25,000 rpm, coolant form AD. Mongtec Precision is a Taiwanese brand, designed and engineered in Taichung, Taiwan.

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Why shrink fit

A shrink fit chuck holds the tool by thermal interference alone: the bore is heated, the shank drops in, and the bore contracts onto it. There is no collet, no nut and no clamping mechanism between the tool and the holder, so the assembly is a single slender body — the highest holding force per unit of diameter, the slimmest profile for deep cavities, and no rotating parts to unbalance at speed.

That is why shrink fit dominates high-speed machining: run-out at ≤ 0.003 mm and balance to G2.5 at 25,000 rpm are achievable because there is nothing in the joint to move.

Specification

Shank	BT (MAS 403 BT, 7/24 taper)
Clamping taper	4.5°
Bore range	Ø3 – Ø32 mm
Run-out (A)	≤ 0.003 mm
Balance	G2.5 / 25,000 rpm
Coolant	Through coolant (form AD) — centre and flange outlet
Article numbers	63
Brand	Mongtec Precision Inc. — Taiwanese brand, designed and engineered in Taichung, Taiwan

Article numbers — dimensions in mm

d = tool bore · D = nose diameter · D1 = body diameter · L = gauge length · L2 = projection · L1, N, G = clamping-screw and balancing-ring data.

BT40 — 33 article numbers

Article no.	Bore Ø d	D	D1	L	L2	L1	N	G
BT40QSF03Q80K	Ø3	15	20	80	53	-	-	-
BT40QSF04Q80K	Ø4	15	20	80	53	-	-	-
BT40QSF05Q80K	Ø5	15	20	80	53	-	-	-
BT40QSF06Q90K	Ø6	21	27	90	63	36	10	M5
BT40QSF08Q90K	Ø8	21	27	90	63	36	10	M6
BT40QSF10Q90K	Ø10	24	32	90	63	42	10	M8x1
BT40QSF12Q90K	Ø12	24	32	90	63	47	10	M10x1
BT40QSF14Q90K	Ø14	27	34	90	63	47	10	M10x1
BT40QSF16Q90K	Ø16	27	34	90	63	50	10	M12x1
BT40QSF18Q90K	Ø18	33	42	90	63	50	10	M12x1
BT40QSF20Q90K	Ø20	33	42	90	63	52	10	M16x1
BT40QSF25Q100K	Ø25	44	53	100	73	58	10	M16x1
BT40QSF32Q100K	Ø32	44	53	100	73	62	10	M16x1
BT40QSF06Q120K	Ø6	21	27	120	93	36	10	M5
BT40QSF08Q120K	Ø8	21	27	120	93	36	10	M6
BT40QSF10Q120K	Ø10	24	32	120	93	42	10	M8x1
BT40QSF12Q120K	Ø12	24	32	120	93	47	10	M10x1
BT40QSF14Q120K	Ø14	27	34	120	93	47	10	M10x1
BT40QSF16Q120K	Ø16	27	34	120	93	50	10	M12x1
BT40QSF18Q120K	Ø18	33	42	120	93	50	10	M12x1
BT40QSF20Q120K	Ø20	33	42	120	93	52	10	M16x1
BT40QSF25Q120K	Ø25	44	53	120	93	58	10	M16x1
BT40QSF32Q120K	Ø32	44	53	120	93	62	10	M16x1
BT40QSF06Q160K	Ø6	21	32	160	133	36	10	M5
BT40QSF08Q160K	Ø8	21	32	160	133	36	10	M6
BT40QSF10Q160K	Ø10	24	34	160	133	42	10	M8x1
BT40QSF12Q160K	Ø12	24	34	160	133	47	10	M10x1
BT40QSF14Q160K	Ø14	27	42	160	133	47	10	M10x1
BT40QSF16Q160K	Ø16	27	42	160	133	50	10	M12x1
BT40QSF18Q160K	Ø18	33	51	160	133	50	10	M12x1
BT40QSF20Q160K	Ø20	33	51	160	133	52	10	M16x1
BT40QSF25Q160K	Ø25	44	53	160	133	58	10	M16x1
BT40QSF32Q160K	Ø32	44	53	160	133	62	10	M16x1

BT50 — 30 article numbers

Article no.	Bore Ø d	D	D1	L	L2	L1	N	G
BT50QSF06Q100K	Ø6	21	27	100	62	36	10	M5
BT50QSF08Q100K	Ø8	21	27	100	62	36	10	M6
BT50QSF10Q100K	Ø10	24	32	100	62	42	10	M8x1
BT50QSF12Q100K	Ø12	24	32	100	62	47	10	M10x1
BT50QSF14Q100K	Ø14	27	34	100	62	47	10	M10x1
BT50QSF16Q100K	Ø16	27	34	100	62	50	10	M12x1
BT50QSF18Q100K	Ø18	33	42	100	62	50	10	M12x1
BT50QSF20Q100K	Ø20	33	42	100	62	52	10	M16x1
BT50QSF25Q110K	Ø25	44	53	110	72	58	10	M16x1
BT50QSF32Q110K	Ø32	44	53	110	72	62	10	M16x1
BT50QSF06Q120K	Ø6	21	27	120	82	36	10	M5
BT50QSF08Q120K	Ø8	21	27	120	82	36	10	M6
BT50QSF10Q120K	Ø10	24	32	120	82	42	10	M8x1
BT50QSF12Q120K	Ø12	24	32	120	82	47	10	M10x1
BT50QSF14Q120K	Ø14	27	34	120	82	47	10	M10x1
BT50QSF16Q120K	Ø16	27	34	120	82	50	10	M12x1
BT50QSF18Q120K	Ø18	33	42	120	82	50	10	M12x1
BT50QSF20Q120K	Ø20	33	42	120	82	52	10	M16x1
BT50QSF25Q120K	Ø25	44	53	120	82	58	10	M16x1
BT50QSF32Q120K	Ø32	44	53	120	82	62	10	M16x1
BT50QSF06Q160K	Ø6	21	32	160	122	36	10	M5
BT50QSF08Q160K	Ø8	21	32	160	122	36	10	M6
BT50QSF10Q160K	Ø10	24	34	160	122	42	10	M8x1
BT50QSF12Q160K	Ø12	24	34	160	122	47	10	M10x1
BT50QSF14Q160K	Ø14	27	42	160	122	47	10	M10x1
BT50QSF16Q160K	Ø16	27	42	160	122	50	10	M12x1
BT50QSF18Q160K	Ø18	33	51	160	122	50	10	M12x1
BT50QSF20Q160K	Ø20	33	51	160	122	52	10	M16x1
BT50QSF25Q160K	Ø25	44	60	160	122	58	10	M16x1
BT50QSF32Q160K	Ø32	44	60	160	122	62	10	M16x1

Source: Mongtec Shrink Fit Chuck catalogue, Ver 2026.

A shrink fit holder needs a shrink fit unit. Tools are changed by induction heating, not by hand. If you do not already run one, ask for the Mongtec shrink fit machine range with your enquiry — holder and unit are quoted together.

Frequently asked

What run-out do Mongtec BT shrink fit chucks hold?

Run-out is ≤ 0.003 mm and the chucks are balanced to G2.5 at 25,000 rpm. There is no collet or nut in the joint, so there is nothing to shift under load or at speed.

Which bore sizes are available in BT?

Bore diameters from Ø3 to Ø32 mm across 63 published article numbers, in several gauge lengths per bore — pick the shortest holder that still reaches the feature.

Do I need a special machine to fit these?

Yes. A shrink fit induction unit heats the bore to release and clamp the tool. Mongtec supplies the machines as well as the holders.

Get a quotation

Send the spindle interface, the tool shank diameters you run and the reach you need. Dimensioned drawings are supplied by email once the enquiry is open.

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