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abat6294 t1_j45txun wrote

Yes, you described it nearly perfectly. I'd make two corrections:

  1. In reality, the torque required to loosen a fastener doesn't always equal the torque applied when it was tightened especially if a lot of time has passed. But if you immediately loosen a fastener after tightening, it should be about the same.

>In order to have a screw torqued to 7 in-lbs, do I apply a load of 1 pound 7 inches away until it no longer rotates?

  1. I think this definition works, but when applied in reality it's more like: Rotate the screw until 7 in-lbs of torque is reached. Because as you know, more and more torque is required to spin a fastener the tighter it gets. When it's loose, you can only apply torque up until it spins.

So if a screw spins with 5 in-lbs of torque, then you simply can't apply 7 in-lbs - it moves before 7 is reached.

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kilotesla t1_j46lmjd wrote

>So if a screw spins with 5 in-lbs of torque, then you simply can't apply 7 in-lbs - it moves before 7 is reached.

Or if you did apply 7-in pounds, you would accelerate it rapidly and it would spend very fast, which isn't really possible with a manual tool although it could be possible with an electric tool, but spinning very fast would make it hard to avoid overshooting the final level of tightening that you want to achieve, and the whole thing becomes simpler when you go slow enough that inertial forces are negligible.

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