Quote:
Originally Posted by andrewwynn
You misunderstood me.
I was saying that you prob wouldn't reach yield until about 160 N·m where 122 is spec. (that could be off a fair amount it might not be a direct ratio).
Reality check;
M10 10.9 spec is 66 N·m and ratio to yield: 88 N·m. In testing, it was right about 90 N·m where the bolt went to plastic and the torque stopped climbing. BTW: a very very weird experience to turn a bolt 45° and no change in torque!
So: a 12mm should handle 140-150 N·m before damage. You should be able to torque to 122 limitless times.
So back my original stance: no problem at all to reuse, i would throw on thread lock if I had handy but wouldn't go out of my way if I didn't.
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At anytime you're fed up with this thread, just stop responding.
As a matter of curiosity, how did you arrive at 88 N.m as the torque at yield. Shouldn't we consider Proof load rather than yield.
Proof load for 10.9 steel is 830 MPa. Effective tensile area (at the root of the thread) is about 50 mm2. So 830 x 50 is 41500 N (41.5 KN Clamping Force) Similarly for M12, it works out to be about 53 KN. Anything above this will cause permanent deformation. So we're at the limit already.
Agree?
01-05-2022, 01:48 PM
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