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Message No. 14768, Started by samingale on 10/19/04
 Why loosening torque is lesser than the tightening torque for bolts/screws Can anybody give me proof for : Opening or loosening torque of screw/bold is always less than the tightening torque. Why this is so? What is the theory behind it?  I want mathematical proof. Thanks for answer in advance.
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Follow-up Messages (10)
 See example 8.1 in Shigley & Mischke  5th edition. No. 22619, Posted by tibbits on 06/14/17, 10:23 PST. Well said, b1ueshift. That leads me to quote my favorite saying about engi... No. 14803, Posted by acroduster1 on 10/25/04, 11:06 PST. The value of a mathematical model is in the accuracy of predicting real wor... No. 14800, Posted by b1ueshift on 10/24/04, 19:30 PST. Please consider standard condition i.e. no corrosion, no imperfections in g... No. 14798, Posted by samingale on 10/22/04, 20:15 PST. not only can the be galling as blueshift pointed out, but after being in se... No. 14785, Posted by rorschach on 10/21/04, 06:33 PST. In my experience, loosening torque is not always less than tightening torqu... No. 14780, Posted by b1ueshift on 10/20/04, 16:05 PST. There are two main forces at work here: Axial tension along the bolt, and t... No. 14778, Posted by tdAlpha on 10/20/04, 15:09 PST. the mathematical answer would have to lie along those lines: while tight... No. 14772, Posted by gerdb on 10/19/04, 15:42 PST. also, if the assembly is subjected to vibration or thermal cycling, the fas... No. 14771, Posted by rorschach on 10/19/04, 05:54 PST. Over time, practically all materials relax a little. When you tighten the ... No. 14769, Posted by acroduster1 on 10/19/04, 03:48 PST.