Abstract: A drilling tool (10) includes a pilot bit (14) and a plurality of mills (16) encircling the pilot bit. The pilot bit and the plurality of mills are each driven by a separate, hydraulically powered turbine or positive displacement motor. (20) The drilling tool does not include a transmission for transmitting power from the turbine or motor to any of the plurality of mills or the pilot bit.

Abstract: An earth boring tool includes two coaxially-aligned, positive displacement motors. One motor turns a pilot bit and the other turns a reamer concentric with the pilot bit. The central bit bores the center of the hole and the reamer enlarges it. The central bit is rotated relatively faster, while rotation of the larger diameter reamer is relatively slow. The tool can thus be used to bore larger diameter holes without slowing drilling rates or adversely affecting performance of the cutter elements due to higher tangential velocities.

Abstract: A drilling tool (10) includes a pilot bit (14) and a plurality of mills (16) encircling the pilot bit. The pilot bit and the plurality of mills are each driven by a separate, hydraulically powered turbine or positive displacement motor. (20) The drilling tool does not include a transmission for transmitting power from the turbine or motor to any of the plurality of mills or the pilot bit.

Abstract: The present disclosure is directed to a method of converting green particles to form finished particles. The apparatus used for sintering incorporates an elongate hollow tube, an insulative sleeve there about to define an elevated temperature zone, and a microwave generator coupled through a wave guide into a microwave cavity incorporated the tube. The particles are moved through the tube at a controlled rate to assure adequate exposure to the microwave radiation. Another form sintered a solid part in a cavity or mold.

Abstract: The present disclosure is directed to a crowned insert. The insert is elongate, right cylinder, two ended body of carbide, preferably bonded tungsten carbide particles. The near end is sized to fit in a hole in a drill bit while the remote end is provided with an enlargement. The enlargement in one embodiment is provided with a circular profile, and has an edge which is chamfered with a radius of curvature to avoid sharp edges. The end of the insert is crowned with a PDC layer integrally cast and bonded thereto so that the enlargement is fully surrounded by the PDC crown.

Abstract: A mud motor bearing assembly is defined by and constructed with a support or base ring having an exposed upper or planar face. On the planar face, a number of PCD disc are attached to define a bearing surface at a common plane. The improved bearing assembly further includes a separate ring or an integral lip serving as a deflector ring brazed to the face of the support ring. The brazed deflector ring alters the fluid flow patterns of drilling fluid in the bearing assembly to reduce support ring erosion.

Abstract: A drill bit for connection on a drill string has a hollow tubular body with an end cutting face and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned in recesses therein having polycrystalline diamond cutting elements mounted on said inserts. The inserts each also have a metal reinforcing shroud secured on the supporting face providing a reinforcement for the polycrystalline diamond cutting elements which is not subject to notch fracture. Each shroud is arranged so that a wall of the associated recess reinforces the shroud against shear forces and reinforces the stud against fracture.

Abstract: A new and improved drill bit for connection on a drill string has a hollow tubular body with an end cutting face and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned therein. Nozzle passages extend from the interior of the bit body through the cutting face, preferably at an angle of about 10.degree.-25.degree. relative to the longitudinal axis of the body, and consist of a passage in the bit body and a removable and interchangeable nozzle member. The nozzle member is secured in place either by peripheral grooves and snap rings or aligned smaller passages in the nozzle member and the bit body having a retaining pin positioned therein.

Abstract: A new and improved drill bit for connection on a drill string has a hollow tubular body with an end cutting face and an exterior peripheral stabilizer surface with cylindrical sintered carbide inserts positioned therein. Nozzle passages extend from the interior of the bit body through the cutting face, preferably at an angle of about 10.degree.-25.degree. relative to the longitudinal axis of the body, and consist of a passage in the bit body and a removable and interchangeable nozzle member. The nozzle member is secured in place either by peripheral grooves and snap rings or aligned smaller passages in the nozzle member and the bit body having a retaining pin positioned therein.