Maximum torque before thread damage
Maximum torque before thread damage
(OP)
I am currently using a 7/16"-20 UN nut to retain a clutch on a shaft. I need to know the max. torque I can apply to the nut before thread damage occurs. I can not seem to find a straight forward calculation. Is there one?
Thanks.
Thanks.
RE: Maximum torque before thread damage
M = F/1000*(0.16p+mu(0.58d2+((do+di)/4)))
where
M is the applied torque in N m
F is the preload developed in N
mu is the friction coefficient for the materials involved
p is the pitch in mm
d2 is the pitch diameter
do is the nut outer contact diameter
di is the nut inner contact diameter (most likely the hole size)
p, d2, do, and di are all dimensions that will come from your part drawings. Unless you specify mu, you will need to estimate this (your nut supplier can provide this for you). F will need to be calculated using the materials properties for your parts. Your nut will have a materials specification, and perhaps a load requirement (e.g. Proof Load). For the shaft, you can use this equation:
F = s * A
where
F = force in N
s = material yield stress in Pa
A = cross-sectional area in m^2
for a 7/16"-20 fastener (assumed to be a solid threaded region on the shaft), A = 7.66 * 10^-5 m^2.
Good luck.
RE: Maximum torque before thread damage
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RE: Maximum torque before thread damage