Bolt Torque Chart

Maximum Tightening Torques for Coarse Threaded Metric Bolts

Property classes (grades) are defined by ISO 898 (Mechanical properties of fasteners made of carbon steel and alloy steel).  This table shows values for threads that have been lightly oiled and the tension is 85% of the proof load.

Size (mm)	Recommended Maximum Tightening Torque (Nm)
	Grade 8.8	Grade 9.8	Grade 10.9	Grade 12.9
M5	7.0	7.8	10.0	11.7
M6	11.8	13.3	17.0	19.9
M8	28.8	32.3	41.3	48.3
M10	57.3	64.1	81.8	95.7
M12	99.8	112	143	167
M16	248	277	354	413
M20	500		690	809
M24	865		1195	1395
M30	1719		2377	2774

These values should only be used when the machine manufacturer has not provided their own. Fine pitch bolts also have different torque levels generally specified in the manufacturer’s documentation.

Maximum Tightening Torques for US Imperial Bolts

This table shows values for threads that have been lightly oiled and the tension is 70% of yield strength. For dry bolts, the values should be increased by 30%.

Size (in)	Recommended Maximum Tightening Torque (lb-ft)
	SAE Grade 2		SAE Grade 5		SAE Grade 8		18-8 S/S
	Coarse	Fine	Coarse	Fine	Coarse	Fine	Coarse	Fine
1/4	4	4.7	6.3	7.3	9	10	6.3	7.8
5/16	8	9	13	14	18	20	11	11.8
3/8	15	17	23	26	33	37	20	22
7/16	24	27	37	41	52	58	31	33
1/2	37	41	57	64	80	90	43	45
9/16	53	59	82	91	115	129	57	63
5/8	73	83	112	128	150	180	93	104
3/4	115	138	200	223	282	315	128	124
7/8	129	144	322	355	454	501	194	193
1	188	210	483	541	682	764	287	289

These values should only be used when the machine manufacturer has not provided their own.