Abstract: A polycrystalline diamond layer attached to a cemented metal carbide structure used as a cutter in a drill bit wherein the cutter has improved toughness or fracture resistance during use through the inclusion of boron, beryllium or the like therein.

Abstract: A polycrystalline diamond layer attached to a cemented metal carbide structure used as a cutter wherein the cutter has improved toughness or fracture resistance during use through the inclusion of boron, beryllium or the like therein.

Abstract: The present invention comprises a cutting structure for earth boring drill bits and a bit including at least one such structure comprising a substantially planar array of cutting elements arranged in substantially contiguous mutual proximity, the array incorporating at least one discontinuity therein dividing it into a plurality of sub-arrays.

Abstract: An improved bearing system for the driven shaft of a downhole motor is shown that provides a main thrust and radial bearing system having means for sealing the bearings in oil at equal or slight pressure above that of the drilling mud inside the drill pipe and insulating the fluid seals and bearings from all possibility of contact with cuttings and debris from the drilling operation. A durable seal having a restricted flow path permitting slow leakage is positioned below the main bearing system in such a relationship to the drilling fluid distribution path that the seals for the oil bath for the bearings are subjected to essentially the same pressure on all sides.