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Posted by Chris Case [75.36.35.9] on Tuesday, February 12, 2013 at 08:46:06 :
In Reply to: Re: Lemme try.... feel free to check math and logic. posted by M Fanoni [70.199.81.34] on Tuesday, February 12, 2013 at 00:30:10 :
Perhaps Grade 0 bolts soft enough to roll threads onto are even softer?
Annealed vs mill hard mild steel?
Nope, a bit of googling tells me grade 1 = 60,000 psi. I've always used 3/4 of tensile for shear.
More googling tells me to double the force if applied suddenly, that may be the crux. Plus the loss of torque in the mechanism. And 3/8 cable has an ultimate strength of over 12,000#. 1/2" 21,000.
IIRC the 8,000# rated winch had 5/16 pin, the later rating of 10,000 had a 3/8 shear pin, that was the only difference.
And oh but wait... the cable on a full spool, not bottom layer, has double the resistance against the shear pin.
So, shock load halves the shear, full spool does too, brings my 50,000# down to 12,500, minus a chunk for friction, 5/16 is pretty close to 3/8" cable ultimate strength.
Maybe. ;^)
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