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View Full Version : Torque setting correction using "claw foot" adapter



J Vernon Bailey
10-22-2003, 07:51
Has anybody done the actual numbers to correct the torque delivered to the fitting when using one of the "claw foot" adapters? When using my 3/8s torque wrench I have always assumed that the delivered torque was close to 10% higher when the claw foot is straight out. I know that the factor is dependent on the length of the lever arm of the torque wrench and the angle and length of the "Claw foot". Comments?

airjohn56
10-22-2003, 10:50
Try this.

Torque Calculator (http://www.norbar.com/twec/index.html)

It is an online calculator.
Hope this helps.

John

britannic
10-22-2003, 11:12
I tested my crows foot against a straight socket in my torque wrench on a bolt using 20ft/lb and wasn't able to detect a difference - obviously my torque wrench isn't sensitive enough, YMMV, but when you're tightening a line nut to the same value it won't matter that much either.

All of my line nuts and injector nozzle nuts were set with a crows foot and have been fine. I believe the torque tolerance for these nuts is around 10% in any case.

ucdavis
10-22-2003, 11:47
Actual vs Reading = ratio of length of actual nut-center-to-end-of-wrench divided by the square-drive-to-end-of-wrench. For crow @ 90* to shaft of wrench (i.e. forming a right angle), ~ 1.0; for crow @ 0* (i.e. extending the length of the wrench by length of crows foot to center of nut) will depend on size of crows foot but is probably ~1.1 as suggested by brittanic. W/crowsfoot turned back toward shaft of wrench it'll be a bit less than 1.0 but likely still within 10%.

turbovair
10-22-2003, 13:24
In the USAF, we were trained that if a crows foot was installed 90 degrees to the torque wrench center line and distance from the center of the broached opening to the center of the square drive was 1" or less, no torque correction was required.Simply torque to the value in the middle of the torque range.