Guide 10 · Fastener Reference Guide

Mild Steel Bolts

ISO metric commercial hex head bolts and set screws — dimensions and properties.

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Property Class 4.6 Bolts Set Screws AS 1111.1

Diameter mm	Pitch mm	af	af	ac	h	h	ds	ds	t	t	t	Spanner mm
		Min	Max	Min	Min	Max	Min	Max	L ≤ 125	125 < L ≤ 200	L > 200
M5	0.80	7.64	8.00	8.63	3.12	3.88	4.52	5.48	16	22	35	8
M6	1.00	9.64	10.00	10.89	3.62	4.38	5.52	6.48	18	24	37	10
M8	1.25	12.57	13.00	14.20	4.92	5.68	7.42	8.58	22	28	41	13
M10	1.50	15.57	16.00	17.59	5.95	6.85	9.42	10.58	26	32	45	16
M12	1.75	17.57	18.00	19.85	7.05	7.95	11.30	12.70	30	36	49	18
M16	2.00	23.16	24.00	26.17	9.25	10.75	15.30	16.70	38	44	57	24
M20	2.50	29.16	30.00	32.95	11.60	13.40	19.16	20.84	46	52	65	30
M24	3.00	35.00	36.00	39.55	14.10	15.90	23.16	24.84	54	60	73	36
M30	3.50	45.00	46.00	50.85	17.65	19.75	29.16	30.84	66	72	85	46
M36	4.00	53.80	55.00	60.79	21.45	23.55	35.00	37.00	–	84	97	55
M42	4.50	63.10	65.00	71.30	24.95	27.05	41.00	43.00	–	96	109	65
M48	5.00	73.10	75.00	82.60	28.95	31.05	47.00	49.00	–	108	121	75
M56	5.50	82.80	85.00	93.56	33.75	36.25	54.80	57.20	–	–	137	85
M64	6.00	92.80	95.00	104.86	38.75	41.25	62.80	65.20	–	–	153	95

Mild Steel Bolts AS/NZS 2451

Diameter	Pitch tpi	af (Min)	af (Max)	ac (Max)	h (Min)	h (Max)	ds (Max)
1/4	20	0.435	0.445	0.510	0.166	0.186	0.280
5/16	18	0.515	0.525	0.610	0.208	0.228	0.342
3/8	16	0.585	0.600	0.690	0.250	0.270	0.405
7/16	14	0.695	0.710	0.820	0.292	0.312	0.468
1/2	12	0.800	0.820	0.950	0.333	0.363	0.530
5/8	11	0.985	1.010	1.170	0.417	0.447	0.665
3/4	10	1.175	1.200	1.390	0.500	0.530	0.790
7/8	9	1.270	1.300	1.500	0.583	0.623	0.915
1	8	1.450	1.480	1.710	0.666	0.706	1.040

ISO Metric Cup Head Square Neck Bolts AS/NZS 1390

Diameter mm	Pitch mm	a	a	k	k	f	f	as	as	t	t	t
		Min	Max	Min	Max	Min	Max	Min	Max	L ≤ 125	125 < L ≤ 200	L > 200
M5	0.80	11.14	11.25	2.50	3.10	2.50	3.10	4.52	5.48	16	22	–
M6	1.00	12.40	13.50	3.00	3.60	3.00	3.60	5.52	6.48	18	24	–
M8	1.25	16.90	18.00	4.00	4.80	4.00	4.80	7.42	8.58	22	28	41
M10	1.50	21.20	22.50	5.00	5.80	5.00	5.80	9.42	10.58	26	32	45
M12	1.75	25.70	27.00	6.00	6.80	6.00	6.80	11.30	12.70	30	36	49
M16	2.00	34.40	36.00	8.00	8.90	8.00	8.90	15.30	16.70	38	44	57
M20	2.50	43.40	45.00	10.00	10.90	10.00	10.90	19.16	20.84	46	52	65
M24	3.00	52.10	54.00	12.00	13.10	12.00	13.10	23.16	24.84	54	60	73

ISO Metric Coach Screws AS/NZS 1393

Diameter mm	af (Min)	af (Max)	ac (Min)	h (Min)	h (Max)	ds (Min)	ds (Max)
M6	9.64	10.00	10.89	3.62	4.38	5.52	6.48
M8	12.57	13.00	14.20	4.92	5.68	7.42	8.58
M10	15.57	16.00	17.59	5.95	6.85	9.42	10.58
M12	17.57	18.00	19.85	7.05	7.95	11.30	12.70
M16	23.16	24.00	26.17	9.25	10.75	15.30	16.70
M20	29.16	30.00	32.95	11.60	13.40	19.16	20.84

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