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Torque Table Hexagon Screws with UNC Threads Table

ANSI Engineering Hardware | Engineering Fastener Torque Specifications
ISO Metric Hard Engineering Data

Preloads and tightening torque for steel shank screws with UNC/UNF threads and head contact area sizes according to ASME B18.2.1, ASME B18.3 and ASME B18.2.2

friction coefficient µ = 0.14, Utilization of minimum yield = 90%

Typical Torque for Hexagon Head Screws with UNC Thrreads

Dimensions

Preloads Fv (kN) (lbf) for Property Class
Tightening torque Ma (Nm) (ft-lbs) for property class
 
 
Grade 5*
Grade 8*
Type 2*
Type 3*
Grade 5*
Grade 8*
Type 2*
Type 3*
Ø
M
[kN]
[lbf]
[kN]
[lbf]
[kN]
[lbf]
[kN]
[lbf]
[Nm]
[ft-lbs]
[Nm]
[ft-lbs]
[Nm]
[ft-lbs]
[Nm]
[ft-lbs]
1/4
20
10.1
2260
14.2
3194
-
-
-
-
12.1
8.95
17.1
12.6
-
-
-
-
5/16
18
16.7
3764
23.7
5319
-
-
-
-
25.7
18.9
36.3
26.7
-
-
-
-
3/8
16
24.9
5594
35.2
7904
-
-
-
-
44.6
32.9
63
46.4
-
-
-
-
7/16
14
34.2
7684
48.3
10858
-
-
-
-
70.9
52.3
100
73.9
-
-
-
-
1/2
13
45.8
10300
64.7
14554
45.8
10300
45.8
10300
109
80.3
154
114
109
80.3
109
80.3
5/8
11
73.2
16464
103
232065
73.2
16464

73.2

16464
213
157
301
222
213
157
213
157
3/4
10
109
24485
154
34599
109
24485
109
24485
383
283
541
399
383
283
383
283
7/8
9
151
33891
213
47889

151

33891
151
33891
614
453
868
640
614
453
614
453
1
8
198
44499
280
62879
198
44499
198
44499
922
680
1303
961
922
680
922
680
1-1/8
7
219
49326
352
79166
-
-
219
49326
1153
850
1850
1364
-
-
1153
850
1-1/4
7
280
62934
449
101005
-
-
280
62934
1618
1194
2597
1916
-
-
1618
1194
1-3/8
6
333
74796
534
120043
-
-
333
74796
2121
1565
3405
2511
-
-
2121
1565
1-1/2
6
406
91358
652
146624
-
-
406
91358
2806
2070
4504
3322
-
-
1618
2070

* Grade 5 (~8.8) and Grade 9 (~10.9) according to SAE J 429, Type 2 and type 3 (~8.8) according to ASTM A325 

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