Torque: Shoot the Engineer

[Wally Choate]

Based on this hard data I began to question my own knowledge (and common sense does say the 2079 tool is a multiplier). My test consisted of a 3 foot length of pipe with a breaker bar stuck in each end and suitable sockets to attach a torque wrench to each end.  One torque wrench was a clicker so I could carefully watch the pointer on the other torque wrench and listen for the click.
At first I got some readings that could support the sine/cosine discussions but then I realized that I was exerting outside forces on the 3 foot pipe.
The final result was 20 foot-pounds applied to one torque wrench resulted in 20 foot pounds at the other torque wrench, not a multiplier of 3 times that amount.  Different wrench angles, that moved my hand closer or farther from the imaginary bolt did not effect the results.
 
Wally
"every engineering formula is the result of empirical data"
 


 
Just locked my highly vaunted $10 HF clicker torque wrench in the vise by 
the handle, square drive up. Torque setting was 100 lb ft.

Put a 19/32" 12 point socket on my Craftsman beam-type wrench, fit the 12 
point part to the square drive of the clicker, and pulled to click: 80 lb 
ft. Not exactly encouraging, but consistent over 10 clicks. The beam type 
wrench is perversely 17" from the handle pivot to the center of the square 
drive.

Removed the socket from both wrenches and placed the 12 point ring end of a 
15mm combination wrench onto the square drive of the clicker wrench, forming 
an angle of 180*. Fit the square drive of the beam wrench to the open end 
of the same combination wrench. That's three wrenches, all in a line. The 
combi wrench is 8.125" from the center of the ring to the place where the 
center of the square drive sits in the open end. With the longer setup, it 
only took 55 lb ft indicated on the beam type to click the clicker.

To make sure I wasn't just getting lucky, I put the socket back in place and 
verified that the first setup indicated 80 lb ft at click.

I worked out the math afterward; it should have been 54 lb ft, so the 
experimental results matched pretty well considering the sloppiness of the 
experiment (could have used a third hand to prevent the wrenches from 
turning about thier long axis.)
$0.02,
Robert




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