Eric F Drake: Methods of manufacturing gradient composite metallic structures. Reed Rock Bit Company, Michael J Caddell, August 16, 1983: US04398952 (134 worldwide citation)

A method is disclosed for forming roller cutters and also for forming cutting teeth for rolling cutter bits, including cutter inserts, cutter teeth formed in place, or formed separately and welded in place, etc., by powder metallurgy as a densified powder metallurgical composite of at least two vary ...

Drake Eric F: Methodes de fabrication de corps metalliques composites gradues, et produits connexes, Methods of manufacturing gradient composite metallic structures and gradient composite metallic products. Reed Rock Bit Company, MEREDITH & FINLAYSON, November 29, 1983: CA1157606

ABSTRACT OF THE INVENTION A rolling cutter drill bit is disclosed having cutters manufactured by powder metallurgy techniques, said cutters hav-ing gradient composite metallic structures in the cutting areas arranged to reduce or eliminate physical and metallic disconti-nuities and stress risers.