twist

I have a question about torquing and the use of a crowsfoot,(crowsfoot creates a short extension to the drive so the values change). I'm fairly obsessive about torquing where the requirement is 15 ft lb or more. Sometimes the use of a crowsfoot is necessary to reach the nut and I've never been sure of how to calculate the difference from a socket to a crowsfoot or extension. Anyone have an answer?

7moore7

Oh that's just a T and L and E that you need to know. And some maths.

Torque Wrench Adapter Extended Calculation - Engineers Edge

twist

thanks!

VTR1000F

Edit: Disregard my ramblings in this post. I am wrong.

Be careful. The entire internet seems to be wrong on this point. The proof shown on Engineer's Edge website is correct, but the formula seems to be universally mis-applied regarding torque wrenches. The only time it or any of the calculators you'll find are correct is when your torque wrench is one foot long. They all seem to forget that the torque wrench is a closed system. If I put a piece of pipe on the handle of the torque wrench to lengthen it, it doesn't change the amount of torque applied to the fastener, it only changes how much force I have to apply with my hand. That is what the formula and all the calculators are calculating - the required force applied to the lever by the user, not the setting required on the torque wrench.

To caculate the required setting in ft-lbs when using an extension like a crowfoot:

Tw = Tf / (1+L)

Where:
Tw = Setting on the torque wrench (ft-lbs)
Tf = Desired torque to be applied to the fastener
L = lenth of extension in feet

Let the argument begin.

(BTW, I did not canvass the entire internet before making the above, generalized statements, but I did search long and hard for at least a few minutes. And I got an "A" in statics and dynamics, so I feel qualified to throw this out on the internet.)

VTR1000F

Well, this is the most difficult thing I've ever had to do. I was w-w-w-w. I was w-w-w-wrong in my post above. It seems this is the one time the entire internet is right and I am wrong. I got stuck on the argument I've had before when lengthening the handle of a torque wrench and failed to consider the entire new system when extending the ratchet end.

This is the second most difficult thing I've ever had to do. 7moore7 was right. Please refer to his posted link for the correct solution to this conundrum.

twist

7moore7

And confused the snot out of me in the meantime.

At least you consider yourself having been the one to save everyone from having cylinders all up in their valves.