Abstract: A drill bit has a formation engaging face through which a plurality of counterbores are formed. A stud assembly having a polycrystalline diamond face thereon is forced into the counterbore in a close tolerance relationship therewith thereby providing frictional forces which prevent movement of the stud assembly respective to the drill bit. A passageway leads from the bottom of the counterbore back to a wall surface of the bit and emerges in spaced relationship respective to the entrance of the counterbore. Hydraulic pressure is effected within the passageway, thereby moving the stud assembly with a piston-like action. The stud assembly is next rotated to bring a new cutting face into cutting position. A tool, made in accordance with the present invention, forces the stud assembly back into the counterbore.

Abstract: Method and apparatus by which the cutting face of a drill bit is renewed. The drill bit has a cutting face comprised of a plurality of radially spaced apart stud assemblies, each received within a socket. A polycrystalline diamond disc forms one end of the stud assembly. The socket is in the form of a counterbore extending angularly into the bit body so that when a marginal end of the stud assembly is forced into a socket, a portion of the face of the diamond disc extends below the bottom of the bit body for engagement with the bottom of a borehole. A passageway communicates with the rear of the counterbore and extends back to a surface of the bit. Fluid pressure is effected within the passageway, thereby developing sufficient pressure differential across the stud assembly to cause the stud assembly to move respective to the socket.

Abstract: A drill bit has a formation engaging face from which there extends a plurality of stud assemblies having a diamond cutting face thereon. Each of the stud assemblies are mounted within a socket by a close tolerance press fit. A reduced diameter rearwardly extending passageway leads from the rear of the socket back up to the face of the bit so that when the diamond face of the stud assembly becomes worn, a tool can be extended through the passageway to the rear of the socket and into contact with the stud assembly to force the stud assembly from the socket. The stud assembly is then rotated a few degrees to present a new cutting edge to the formation, and pressed back into the socket, thereby returning the drill bit to like new condition.