I'm making a mechanical thumb for a kubota L-48 backhoe. The pivot pins are
1.25" x 10". What type steel would you recommend for the pins. I will need to drill and cut these, but they obviously need to be tough enough not to bend/shear.
When I worked for a Skid Steer manufacturer we made the pivot pins out of Stressproof. The bars come generally on size within a thou or two of the stated size, and the material is generally hardened to around
32Rc. If it is a very high stress area the next step up would be 4340HT. It comes in hot rolled so you would need the next size up and turned down to size.FWIW, I've used W1 from Mcmaster Carr on my hoe, no problems. Main reason is they will sell a three foot piece and have it to your door by tommorrow.
4140 would be another good choice.Karl
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