Related Resources: hardware

Torque for Hexagon Head Screws with UNF 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 UNF Threads Table

Size
VPreloads Fv (kN) for property class
Grade 5*
Grade 8*
Type 2*
Type 3*
Ø
M
[kN]
[lbf]
[kN]
[lbf]
[kN]
[lbf]
[kN]
[lbf]
1/4
28
11.8
2653
16.7
3749
-
-
-
-
5/16
24
18.9
4252
26.7
6008
-
-
-
-
3/8
24
28.9
6486
40.8
9165
-
-
-
-
7/16
20
39.0
8758
55.0
12375
-
-
-
-
1/2
20
52.8
11861
74.6
16760
52.7
11861
52.7
11861
5/8
18
84.7
19050
120
26918
84.7
19050
84.7
19050
3/4
16
124
27814
175
39302
124
27814
124
27814

 

Size
Tightening torque MA (Nm) for property class
Grade 5*
Grade 8*
Type 2*
Type 3*
Ø
M
[Nm]
[ft-lbs]
[Nm]
[ft-lbs]
[Nm]
[ft-lbs]
[Nm]
[ft-lbs]
1/4
28
13.8
10.2
19.5
14.4
-
-
-
-
5/16
24
28.3
20.9
40.0
29.5
-
-
-
-
3/8
24
50.0
36.9
70.7
52.2
-
-
-
-
7/16
20
78.6
57.9
111
81.9
-
-
-
-
1/2
20
122
89.7
172
127
122
89.7
122
89.7
5/8
18
239
176
337
249
239
176
239
176
3/4
16
423
312
597
441
423
312
423
312

* 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

Related: