1
Charles A Hartwell: Stabilizer. Gunn Lee & Jackson, July 14, 1981: US04277869 (18 worldwide citation)

An improved stabilizer is disclosed. In the preferred and illustrated embodiment, a built-up spline is disclosed. The spline is made by drilling a set of holes in a blank of relatively soft metal and inserting hardened inserts into the metal. Typical inserts are made of tungsten carbide. They may be ...


2
Charles A Hartwell: Segmented hardfaced collar for tool joints. Gunn Lee & Jackson, October 27, 1981: US04296973 (12 worldwide citation)

A segmented hardfaced collar for tool joints is disclosed. In the preferred and illustrated embodiment, a wear resistant tool joint suitably dressed for use is disclosed. It is formed at externally upset box tool joints. The apparatus comprises, in the preferred embodiment, a pair of semicircular se ...