Thermally stable polycrystalline diamond drill bit

Claim 1

A diamond drag type drill bit for drilling in an earthen formation comprising; a body forming a first cutting end formed from a matrix material and a second open threaded pin end, said body further forming a plenum chamber adapted to receive drilling fluid routed through a threadably attachable drill string, at least one discharge port is formed by said first cutting end, said discharge port being in fluid communication with said plenum chamber, said first cutting end formed of said matrix material consists of a multiplicity of substantially radially disposed ridges forming a leading surface, a heel surface and a trailing surface with flow channels formed therebetween, the flow channels intersect said discharge port and radially extend outwardly toward a peripheral edge formed by said cutter end, said ridges contain, along their leading, radially extended surfaces, a multiplicity of substantially equidistantly spaced diamond cutters embedded within said matrix material and having each of their cutting edges formed by said cutters extend beyond said leading surface of said ridge forming an apical edge thereby, and the space formed between each extended diamond cutter and a surface of said matrix material contains a filler material aligned along said apical edge that is less hard than either the diamond or the supporting matrix material forming the first cutting end of the drag bit, said filler material rapidly wears away during operation of the bit in said earthen formation allowing the diamond cutters to protrude an extent necessary to obtain optimum formation cutting rates and dispersion of drilling fluid for maximum bit penetration.