Torque to failure for M8 socket head cap screws?
Torque to failure for M8 socket head cap screws?
(OP)
Anyone know through testing how much torque it takes break an M8 made of A2-70 stainless steel.
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Torque to failure for M8 socket head cap screws?
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RE: Torque to failure for M8 socket head cap screws?
The material's tensile strength is 586 MPa. The transition radius under the head should be 0.6mm, the head is 13mm in dia, and the body diameter looks to be 8mm.
Stress concentration ~ 1.46
max Shear stress = K * T*c/J
c = 7.78mm
J ~ pi*(d^4)/32 = 402 mm^4
max stress = 586 MPa
K ~ 1.46
586 MPa = 1.46 * T * 8mm / (402mm^4)
T ~ 20.2 N-m ~ 14.9 lbf-ft
Your mileage may vary, and my calculations may be wrong, so you'll probably still want to shear a screw to find out.
RE: Torque to failure for M8 socket head cap screws?
Best way to find out is to take a handfull of parts and test them to failure.
Dick
RE: Torque to failure for M8 socket head cap screws?
Regards,
Cory
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RE: Torque to failure for M8 socket head cap screws?
I guess the lesson is that these forums are a useful place to get starting information, but anything said should be verified before use.