how to calculate a shear pin
how to calculate a shear pin
(OP)
Hi,
I want to install a shear pin as a security device.
I think i do not use the proper way to calculate....
I've got a 3/4 shaft with 100 lbs-in of torque.
I need a shear pin made of bronze (shear constraint 6.5x10^6 psi).
I've found a pin dia of 0.005". something wrong i guess?!?
Can you help me.
Thanks
I want to install a shear pin as a security device.
I think i do not use the proper way to calculate....
I've got a 3/4 shaft with 100 lbs-in of torque.
I need a shear pin made of bronze (shear constraint 6.5x10^6 psi).
I've found a pin dia of 0.005". something wrong i guess?!?
Can you help me.
Thanks





RE: how to calculate a shear pin
RE: how to calculate a shear pin
Make more sens with a 0.069 dia pin....
I thought that the shear modulus was the appropriate value.
(machinery's hanbook 26th edition page 384)
I use 60 000 psi (ultimate tensile strength)
RE: how to calculate a shear pin
Also, you said you had 100 in lb of torque, and we are discussing a pin which should shear at about that load. If you want to carry that load, but shear at some higher value to prevent damage, you will need a larger pin.
Glad I could be of help.
Regards,
Lcubed
RE: how to calculate a shear pin
Phosphor Bronze cold rolled shear 40 ksi
D=0.092" or 3/32"
RE: how to calculate a shear pin
This method was widely used to protect overhead push-chain conveyors, some 20-30yrs ago before the advent of 'tripping' clutches
RE: how to calculate a shear pin
I agree with your hardened bushing suggestion but I would differ with the "necking down" logic. The face to face contact zone will pretty well define the shear plane of the pin. I think the real reason some pins are necked down is to custom tailor or fine tune the shear area.
We make hay balers and the things still use shear bolts, some of which shear on an all too frequent basis depending on the operator!