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mikestock's avatar
mikestock
Explorer
Jul 30, 2015

Myth that socket extensions change torque wrench readings

I have had mechanics and one person who builds competition airplanes swear that torque wrenches are inaccurate when an extension is added. To me, this flies in the face of the Action, Equal and Opposi...
Huntindog's avatar
Huntindog
Explorer
Aug 04, 2015
mikestock wrote:
Hunting Dog,
Thought you had previously disqualified yourself. Only from the math calcualtions.

Don't know how we got to this crowfoot situation, but the angle of the crowfoot makes all the difference, because it changes the moment arm length, which is the distance from wherever the sensor is on the wrench handle to the target load, which is the nut or bolt. Of course, this distance changes every time the wrench ratchets.


When ever I need to break a stubborn bolt loose, I reach for my longest wrench or a cheater bar. With a long enough wrench I can exert more force on the bolt with my pinky finger than I can with my whole body and a short wrench.

The crows foot is just a lever that acts as a torgue multiplier as it's input side is attached to the output of the TQ wrench. The TQ wrench output normally would rotate on the center axis of the bolt. When a crows foot of any length is used between the TQ wrench and the bolt, the output of the TQ wrench is multiplies as it can no longer rotate on the bolts center axis. It now orbits the bolt covering a much larger path as it outputs the original force to the input end of the crows foot, which will ALWAYS mutiply whatever force is on the input end to the output end.
So the TQ wrenches target load is now the crows foot. And the crows foot target load is the bolt. Take the racheting out of the equation if you want, and think if an old dial wrench, as it needlesly muddies the question which orginally was a 90 degree angle

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