SJ Type | B&B TechnoSolutions

Three-jaw standard self-centring lathe chuck with stepped jaws on a white background.

Dimensional drawing of an SJ type self-centring chuck with labeled sizes d1 through L3.

SJ type chucks ship with one set of forward jaws, one set of reverse jaws, a chuck key, and mounting bolts. These are the everyday scroll chucks for production turning — interchangeable parts, ground ways, and sizes from 80 mm up.

SeriesSJ Type
Size range80 mm to 610 mm
Configuration3, 4, or 6 jaws
PricingBy quote. We’ll beat a competitor price on the same spec.

Body

High-tensile Grade 25 cast iron (semi-steel), 180–210 BHN.

Jaws

Low-carbon case-hardening steel, heat treated to 55–60 HRC.

Scroll

Forged wear-resistant alloy steel, 40–45 HRC.

Pinion

Case-hardening alloy steel, 40–45 HRC.

Features

Body knob and jaw ways hardened and ground.
Scroll bore and threads ground from both sides.
Jaw teeth ground from both sides.
Hardened and ground pinion.
Accuracy better than 0.05 mm on 160–315 mm chucks.
Interchangeable parts for service and rebuilds.

Request a quote Dimensional PDF

Dimensional data

Swipe sideways to see every column.

SJ type self-centring chuck dimensions in millimetres. Weights in kilograms.
Nominal size	d2 H7	P.C.D. d3	Tol. on d3	d5	h1	h2	D	L	K	L1	L2	L3	Jaw thickness	Handle square	Wt SJ3	Wt SJ4	Wt SJ6
80	56	67	±0.20	16	44	14	3	32	M6	11	6	6	10.5	6	1.3	—	—
100	70	83	±0.25	20	50	18	3	42	M8	14	8	8	14	8	2.4	2.4	—
110	80	94	±0.25	22	55	18	4	42	M8	14	8	8	14	9	3.1	3.5	—
125	95	108	±0.25	33	60	22	4	48	M8	16	9	9	16.5	9	4	4	4.5
160	125	140	±0.30	42	67	29	5	65	M10	20	12	12	18	10	8	8	9
200	160	176	±0.35	55	75	31	5	76	M10	24	12.5	12.5	22	11	13	14	14
250	200	224	±0.35	76	86	36	6	97	M12	30	13	14	28.5	12	24	24	24
270	220	245	±0.35	90	86	36	6	97	M12	30	13	14	28.5	12	26	27	27
315	260	286	±0.40	108	86	36	6	120	M12	38	14	14	28.5	14	36	37	38
375	320	349	±0.40	140	95	58	6	140	M12	38	25	25	34	16	56	62	64
400	330	362	±0.40	150	105	58	8	160	M16	40	25	25	34	16	70	72	78
500	433	465	±0.50	203	135	63	8	170	M16	48	25	25	40	16	102	105	110
610	538	567	±0.50	260	130	80	10	200	M16	55	35	35	50	19	180	182	188

Taken from the series datasheet. Confirm spindle nose, bore, and jaws on the quote. The PDF drawing governs.

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