Method for case hardening rock bits and rock bits formed thereby

Abstract

In the method of manufacturing case hardened rock bits formed of a previously known conical profile for containing spaced apart cutter inserts in a common circumferential row about the cone, carburizing is applied uniformly over the entire conical surface of the cutter blank. Without removing any of the applied carburizing composition elsewhere, the compact lands are counterbored of diameter slightly larger than the socket cavity to be drilled, and to a depth below the carburized case so as to remove the carburized case thereat. The cutter blank is then hardened after which the insert cavities are drilled concentrically through the previous counterbores followed by a pressing of the individual inserts in an interference fit into the cavities. This results in continuous uninterrupted case hardening in the land areas between adjacent inserts. Also disclosed is a rock bit formed in accordance with the aforesaid method.