Imperial Screw Torques
Imperial Screw Tightening Torques - Nm
Size Ø (mm) Strength 2
No Marks on head
Inches mm Coarse
Thread
1/4
6.4
5.6
5/16
7.9
10.8
3/8
9.5
20.3
7/16
11.1
33.9
1/2
12.7 47.5
9/16
14.3 67.8
5/8
15.9 95
3/4
19.1
169.5
7/8
22.2 176.3
1
25.4 257.6
1 1/8
28.6 359.3
1 1/4
31.8 508.8
1 3/8
34.9 664.4
1 1/2
38.1 881.3
68
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Strength 5
3 Marks on head 6 Marks on head
Fine
Coarse
Fine
Thread
Thread
Thread
6.3
8.6
9.8
12.2
17.6
19.0
23.0
31.2
35.2
36.6
50.2
55.6
54.2
77.3
86.8
81.3
108.5
122
108.5
149.1
169.5
189.8
271.1
298.3
196.6
433.9
474.5
278
650.8
718.6
406.8
813.5
908.4
562.7
1139
1261
759.3
1491
1695
989.8
1966
2237
Strength 8
Coarse
Fine
Thread
Thread
12.2
13.5
24.4
27.1
44.7
50.2
70.5
78.6
108.5
122.0
156
176.3
216
244
380
427
610
678
915.2
1017
1302
1458
1844
2034
2414
2753
3128
3602