Rev. 8
1–15
TORQUE VALUES
Torque applied is for the size of the bolt shank not the wrench size. On smaller bolts
use a torque wrench calibrated in inch pounds, not foot pounds.
When tightening fasteners with self-locking nuts the chart values must be
modified. The friction drag torque must be determined and then added to the
standard torque from the table. Due to the friction of the locking device noticeable
torque is required just to turn the nut onto the threads and does nothing to actually
tighten the parts together and stretch the bolt (clamp load). This is called friction drag
(or prevailing) torque. Run the nut down to where it nearly contacts the washer or
bearing surface and check the friction drag torque required to turn the nut. (At least one
thread should protrude from the nut). Add the friction drag torque to the standard torque.
This sum is referred to as the final (or total) torque, which should register on the
indicator or setting for a snap-over type torque wrench.
The propeller manufacturer and the engine manufacturer have specific torque
requirements for their equipment. Consult the appropriate manual for that information.
Contact + 3/4 Turn or as Specified
Bolt
size
Threads per inch
AN310, AN315,MS20365
(Portions of this information has been adapted from AC 43. 13)
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