How long is the thread on an M12 × 100 DIN 931 bolt?

30 mm, the value for lengths up to 125 mm. An M12 × 150 bolt has 36 mm of thread.

DIN 931 / ISO 4014 hex bolt dimensions, M3 to M24

DIN 931 / ISO 4014 dimensions

DIN 931 / ISO 4014 dimensions
Size	Pmm	snom, mm	knom, mm	emin, mm	cmax, mm	bl ≤ 125, mm	b125 < l ≤ 200, mm	bl > 200, mm
M3	0.5	5.5	2	6.01	0.4	12	18	31
M4	0.7	7	2.8	7.66	0.4	14	20	33
M5	0.8	8	3.5	8.79	0.5	16	22	35
M6	1	10	4	11.05	0.5	18	24	37
M8	1.25	13	5.3	14.38	0.6	22	28	41
M10	1.5	16	6.4	17.77	0.6	26	32	45
M12	1.75	18	7.5	20.03	0.6	30	36	49
M14	2	21	8.8	23.36	0.6	34	40	53
M16	2	24	10	26.75	0.8	38	44	57
M18	2.5	27	11.5	30.14	0.8	42	48	61
M20	2.5	30	12.5	33.53	0.8	46	52	65
M22	2.5	34	14	37.72	0.8	50	56	69
M24	3	36	15	39.98	0.8	54	60	73

Where DIN 931 differs from ISO 4014

Size	sISO 4014	sDIN 931	eISO 4014	eDIN 931
M10	16	17	17.77	18.9
M12	18	19	20.03	21.1
M14	21	22	23.36	24.49
M22	34	32	37.72	37.72

DIN 931 is withdrawn but parts to it are still sold. Only the sizes listed here differ; in every other size both standards give the same part. Pick the standard in the selector above to get the matching CAD files.

Dimensions in millimetres unless stated. Select a row to load its CAD files above.

DIN 931 thread length

The thread length b has three values per size: one for lengths up to 125 mm, one for 125 to 200 mm and one above 200 mm. At M12 it is 30, 36 and 49 mm. The CAD files mark the threaded part with thin lines on the THREAD layer.

DIN 931 vs ISO 4014

As with the fully threaded hex screw, DIN 931 differs only in the width across flats of M10, M12, M14 and M22. Those sizes have their own DIN 931 files, listed under the table. The fully threaded version of the same bolt is DIN 933 / ISO 4017.

DIN 931 bolts: common questions

How long is the thread on an M12 × 100 DIN 931 bolt?: 30 mm, the value for lengths up to 125 mm. An M12 × 150 bolt has 36 mm of thread.

Sources the dimensions were checked against (8)