Anchored hardened cutter inserts

Claim 1

A drilling tool having rotary cutters thereon, the cutters having cylindrical sockets therein for hardened cylindrical inserts, wherein the improvements comprises: generally cylindrical molded metal inserts, each having a working end and a base end and being of a material whose hardness is such that machining of the inserts is impractical, each insert having on at least one sidewall portion thereof abutment means directed more toward said working end than toward the base end, said inserts being located in the sockets in said cutters with said abutment means laterally adjacent a portion of the material of the cutter in which the insert is mounted, said portions of the material of the cutters being stacked against said abutment means to retain the inserts in the cutter sockets, and said abutment means also being so disposed that some of the staked material of the cutters will lie in the path of rotation of the abutment means and within the cylindrical confines of the inserts.

Claim 7

The method of producing and anchoring hardened metal inserts in rotary drilling cutters which includes: molding sintered metal inserts of generally cylindrical cross section with outer working ends, and in the molding operation forming on the inserts within the confines of their otherwise cylindrical cross section and inwardly from their outer working ends noncylindrical abutment surfaces having portions of their greater radial depth adjacent the outer working ends of the inserts than portions more axially inward therefrom, centerless grinding the inserts to substantially true cylindrical cross section, forming cylindrical sockets in the cutters, press fitting the inserts in the cutter sockets, and staking the metal of the cutter adjacent said cutter sockets and their received inserts to displace metal of the socket walls inwardly against the noncyliNdrical abutment surfaces of the inserts.

Claim 8

The method of producing and anchoring hardened metal inserts in rotary drilling cutters which includes: molding sintered metal inserts of generally cylindrical cross section with outer working ends, and in the molding operation forming on the inserts within the confines of their otherwise cylindrical cross section and inwardly from their outer working ends noncylindrical abutment surfaces having portions of their greater radial depth adjacent the outer working ends of the inserts than portions more axially inward therefrom, centerless grinding the inserts to substantially true cylindrical cross section, forming cylindrical sockets in the cutters, press fitting the inserts in the cutter sockets, and staking the metal of the cutter adjacent said cutter sockets and their received inserts to displace metal of the socket walls inwardly against the noncyliNdrical abutment surfaces of the inserts.