Abstract: A cutting tool or drill bit (10) has a shank (12) with two ends. A chucking end (14) is on one end of the shank (12) and a cutting end (16) is on the other end of the shank (12). At least one flute (30) is formed on the shank (12) between the chucking (14) and cutting ends (16). The flute (30) includes a web (36) and a debris channel (32). The web (36) includes a first (38) and second (40) surface continuous with a debris channel side wall (34). The first surface (38) is substantially parallel to the shank longitudinal axis (18) and the second surface (40) is on an angle from about 100.degree. to about 120.degree. with respect to the shank longitudinal axis (18). The second surface forms the base of the debris channel or groove (32) with the debris channel side wall (34). The debris channel side wall (34) is on an angle from about 10.degree. to about 20.degree. with respect to the shank longitudinal axis (18).

Abstract: A cutting tool or drill bit (10) has a shank (12) with two ends. A chucking end (14) is on one end of the shank (12) and a cutting end (16) is on the other end of the shank (12). At least one flute (30) is formed on the shank (12) between the chucking (14) and cutting ends (16). The flute (30) includes a web (36) and a debris channel (32). The web (36) includes a first (38) and second (40) surface continuous with a debris channel side wall (34). The first surface (38) is substantially parallel to the shank longitudinal axis (18) and the second surface (40) is on an angle from about 100.degree. to about 120.degree. with respect to the shank longitudinal axis (18). The second surface forms the base of the debris channel or groove (32) with the debris channel side wall (34). The debris channel side wall (34) is on an angle from about 10.degree. to about 20.degree. with respect to the shank longitudinal axis (18).

Abstract: There is described a coupling for in use lifting and supporting oil drilling strings while allowing rotation of the drill strike and calculation of mud through the drill. The coupling comprises an upper body and a lower body. The lower body is rotatably mounted on the upper body and has support means for lifting drill pipes. The coupling is provided with a through passage for supply of mud to the drill pipes and a valve member is provided to control mud supply.