Torque to unscrew a bolt
Torque to unscrew a bolt
(OP)
I need to know how much torque is required to unscrew a nut or a screw.
Is there a standard ratio which is working for every case? I mean, I think it is closely related to the tightening torque, so it should always be something like 50% of the tightening torque.
I could calculate that but I'm sure there is a rule of thumb...
Thanks
Jeff
Is there a standard ratio which is working for every case? I mean, I think it is closely related to the tightening torque, so it should always be something like 50% of the tightening torque.
I could calculate that but I'm sure there is a rule of thumb...
Thanks
Jeff





RE: Torque to unscrew a bolt
I've looked in countless engineering books, But knowbody seems to offer torque calculations for undoing bolts. They offer heaps of info regarding tightening torque, but not the opposite. Have you tried emailing boltscience or looking on there website.
www.boltscience.co.uk
I hope you find the info you need.
Regards
Bryan
RE: Torque to unscrew a bolt
RE: Torque to unscrew a bolt
Jonralph's values seem reasonable, though I have not seen anything published on untightening torque.
RE: Torque to unscrew a bolt
RE: Torque to unscrew a bolt
RE: Torque to unscrew a bolt
RE: Torque to unscrew a bolt
I presume, we are discussing a new joint without any ageing.
RE: Torque to unscrew a bolt
But I think it is interesting to know about bolts. I will try to experiment, if I find the time to do it, with a few bolt sizes. If and when I get results, I will let you know.
RE: Torque to unscrew a bolt
Blacksmith