Stainless Steel Fasteners Pre-Load and Tightening Torques

Stainless Steel Fasteners Pre-Load and Tightening Torques

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This table shows the maximum permissible tightening torques and the resulting maximum preload for A1, A2 and A4 stainless steel fasteners.

For guidance only

Thread Size	Coeff Friction	Preload (Kn) Property class			Tightening Torque (Nm) Property class			Min Breaking Torque
		A1-50	A2-70	A4-80	A1-50	A2-70	A4-80	A1-50	A2-70	A4-80
M1.6	0.1	0.4	0.55	0.55	0.1	0.1	0.2	0.15	0.2	0.24
	0.2	0.3	0.35	0.35	0.1	0.2	0.35
	0.3	0.2	0.3	0.3	0.2	0.25	0.45
M2.0	0.1	0.5	0.6	0.6	0.15	0.2	0.3	0.3	0.4	0.48
	0.2	0.4	0.5	0.5	0.25	0.3	0.4
	0.3	0.25	0.36	0.36	0.4	0.4	0.55
M2.5	0.1	0.65	0.9	0.9	0.25	0.45	0.6	0.6	0.9	0.96
	0.2	0.4	0.5	0.5	0.45	0.6	0.65
	0.3	0.3	0.3	0.3	0.6	0.75	0.8
M3.0	0.1	0.9	1	1	0.85	1	1.3	1.1	1.6	1.8
	0.2	0.6	0.65	0.65	1	1.1	1.6
	0.3	0.4	0.45	0.45	1.25	1.35	1.85
M4.0	0.1	1.08	2.97	2.97	0.8	1.7	2.3	2.7	3.8	4.3
	0.2	1.12	2.4	2.4	1.3	2.6	3.5
	0.3	0.9	1.94	1.94	1.5	3	4.1
M5.0	0.1	2.26	4.85	4.85	1.6	3.4	4.6	5.5	7.8	8.8
	0.2	1.83	3.93	3.93	2.4	5.1	6.9
	0.3	1.49	3.19	3.19	2.8	6.1	8
M6.0	0.1	3.2	6.85	6.85	2.8	5.9	8	9.3	13	15
	0.2	2.59	5.54	5.54	4.1	8.8	11.8
	0.3	2.09	4.49	4.49	4.8	10.4	13.9
M8.0	0.1	5.86	12.6	12.6	6.8	14.5	19.3	23	32	37
	0.2	4.75	10.2	10.2	10.1	21.4	28.7
	0.3	3.85	8.85	8.85	11.9	25.5	33.9
M10.0	0.1	9.32	20	20	13.7	30	39.4	46	65	74
	0.2	7.58	16.2	16.2	20.3	44	58
	0.3	6.14	13.1	13.1	24	51	69
M12.0	0.1	13.6	29.1	29.1	23.6	50	67	80	110	130
	0.2	11.1	23.7	23.7	34.8	74	100
	0.3	9	19.2	19.2	41	88	117
M14.0	0.1	18.7	40	40	37.1	79	106	210	290	330
	0.2	15.2	32.6	32.6	56	119	159
	0.3	12.3	26.4	26.4	66	141	188
M.16.0	0.1	25.7	55	55	56	121	161
	0.2	20.9	44.9	44.9	86	183	245
	0.3	17	36.4	36.4	102	218	291
M18.0	0.1	32.2	69	69	81	174	232
	0.2	26.2	56.2	56.2	122	260	346
	0.3	21.1	45.5	45.5	144	380	411
M20.0	0.1	41.3	88.6	88.6	114	224	325
	0.2	33.8	72.4	72.4	173	370	494
	0.3	27.4	58.7	58.7	205	439	586
M22.0	0.1	50	107	107	148	318	424
	0.2	41	88	88	227	488	650
	0.3	34	72	72	272	582	776
M24.0	0.1	58	142	142	187	400	534
	0.2	47	101	101	284	608	810
	0.3	39	83	83	338	724	966
M27.0	0.1	75			275
	0.2	61			421
	0.3	50			503
M33.0	0.1	91			374
	0.2	75			571
	0.3	61			680
M36.0	0.1	114			506
	0.2	94			779
	0.3	76			929
M39.0	0.1	135			651
	0.2	110			998
	0.3	89			1189
	0.1	162			842
	0.2	133			1300
	0.3	108			1553

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