Operation and maintenance manual
Section 300-0080
Miscellaneous - Standard Bolt and Nut Torque Specifications
SM 1238 2-98
4
SELF-LOCKING FASTENERS
Self-locking fasteners develop a measured gripping
action or torque and provide a renewed locking action
after being removed and reinstalled to their original
mating part. The self-locking fasteners used on this
equipment meet specifications necessary to allow the
fasteners to be reused up to five times. Whenever a
self-locking fastener is removed, the head of the
fastener should be deeply scribed or otherwise
marked to record the number of times the fastener has
been used. Do not use a self-locking fastener more
than five times.
The following table shows the minimum torque
specifications allowed to remove self-locking fasteners
after the initial break-away torque has been achieved.
Any self locking fastener that can be removed with
less than the prevailing torque value shown in the
table should be discarded, even if the fastener has not
yet been reused five times.
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