tm_wilhelm wrote:
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.