Chapter 5 General Reference 115
Thread Torques
WARNING
Anytime a gear-bearing bolt is removed, it must be replaced with a new bolt of the identical
grade and size. Once a bolt has been torqued to 75% of its proof load and then removed, the
torque coefficient may no longer be the same as when the bolt was new thus giving
indeterminate clamp loads after torquing. Failure to replace gear-bearing bolts may result in bolt
failure due to metal fatigue, causing serious injury or DEATH.
When using the torque data in the torque charts, the following rules should be observed.
1 Bolt manufacturer’s particular specifications should be consulted when provided.
2 Flat washers of equal strength must be used.
3 All torque measurements are given in foot-pounds. To convert to inch-pounds, multiply by
12.
4 Torque values specified are for bolts with residual oils or no special lubricants applied. If
special lubricants of high stress ability, such as Never-Seez compound graphite and oil,
molybdenum disulphide, colloidal copper or white lead are applied, multiply the torque values
in the charts by the factor .90. The use of Loctite does not affect the torque values.
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