On Jul 16, 6:24*pm, Jim Wilkins wrote:

I think up to ~80% of the tightening force on a screw can be lost to
friction. Compare the torque to tighten with that to loosen.

jsw

This seems too obvious to mention, but I will anyway. The friction
depends on the lubrication. A ball bearing thrust bearing or a roller
bearing would also help.

You can find a lot of the type of information you want in web sites
that are about torquing bolts. Especially on the effects of
lubrication.

Perhaps you could incorporate Belleville washers to give you an idea
of the force applied. Belleville washers can be stacked to increase
the force necessary to flatten them.

Dan