TM 10-4520-259-13&P
*Torque given is for clean, dry threads. Reduce torque by 10percent when engine oilis used as a
lubricant.
Table H-2. Locknut Breakaway Torque Values
NOTE
To determine breakaway torque, thread locknut onto screw or bolt until at least two
threads stick out. Locknut shall not make contact with a mating part. Stop the
locknut. Torque necessary to begin turning locknut again is the breakaway torque.
Do not reuse locknuts that do not meet minimum breakaway torque.
Minimum breakaway torque
Thread
size
lb-in.
(N.m.)
10-32
2.0
(0.23)
1/4-28
3.5
(0.40)
5/16-24
6.5
(0.73)
3/8-24
9.5
(1.07)
7/16-20
14.0
(1.58)
1/2-20
18.0
(2.03)
9/16-18
24.0
(2.71)
5/8-18
32.0
(3.62)
3/4-16
50.0
(5.65)
7/8-14
70.0
(7.91)
1-12
90.0
(10.17)
1-1/8-12
117.0
(13.22)
1-1/4-12
143.0
(16.16)
H-3/(H-4 blank)
