Abstract: A roller cone drill bit includes a bit body, at least one leg extending downward from the bit body, a journal on each leg, and a roller cone mounted on each journal. A ball race is configured between each journal and roller cone, and a plurality of retention balls is disposed within each ball race. A ball hole extends from the back face of each leg to the ball race, and a ball hole plug fits within the ball hole. The ball hole plug is secured to the leg by a friction stir weld.

Abstract: A lubricating nutating single cone drill bit 10 is disclosed. Bit 10 includes a bit shank 12 with an axially skewed bore 18 rotatably retaining a cutter body 22. A plurality of cutter elements (46, 48) are affixed to the cutter body 22. Bearings (26, 28, 30, 32) enable rotation of the cutter body 22 and lubricant is dispensed to the bearings from a lubricant chamber (76, 76?) by a plunger 80 driven by drilling fluid. A method to drill includes attaching the bit 10 to a drill string, engaging the bit 10 into a formation (WB), pumping a drilling fluid into a plunger 80 in the lubricant chamber 76 to dispense lubricant to the bearings (26, 28, 30, 32). The method can include pumping the drilling fluid through a fluid passage 90 in the bit 10 and out of a low pressure orifice 94 on the cutter body 22.

Abstract: A modular drill bit mounts legs within recesses in a body which are parallel to the central axis of the body using threaded studs with tapered outer portions, in conjunction with an attached pin having recesses therein receiving the upper ends of the legs. The lower ends of the legs terminate in spindles of open face configuration rotatably receiving cones thereon for rotation via a arrangement of bushings, roller bearings and thrust bearings, and a plurality of seals which slide and therefore rotate relative to both the leg spindle and the cone with the help of pressure compensating apparatus. A bushing disposed in the cone-leg spindle interface has oil-lubricated rubber rods disposed in apertures therein to prevent lock-up on an adjacent bearing surface. The cone is held in the leg spindle by a lock nut forming one end of a race for receiving rollers of a roller bearing, in conjunction with a ring-nut secured to an extended portion of the cone protecting the leg from wear and damage.

Abstract: An underreamer including a body having a bore therethrough, an arm mounted at its upper end to the body, a sleeve member detachably secured to the lower end of each arm and adapted to receive the frictional wear caused by the rotation of the conical cutter mounted thereto. Bearings and seals disposed between the cutter and the sleeve member provide smooth rotation of the cutter. In addition, locking pins and bearings extending between the arm and the sleeve member secure the sleeve on the arm. The arms are pivotally mounted in slots in the body and mechanical structure is provided for moving the arms to their cutting position with their lower ends positioned radially outward from the body.

Abstract: A removable ball loading hole plug for a rotary cutter rock drilling bit having an offset head portion to position the inner race end axially and rotationally. A locking groove on the outer surface of the offset head portion coacts with an adjacent end of a threaded retainer for removable locking engagement therewith.

Abstract: In a rotary drill bit assembly, comprising a drill bit body, at least one trunnion and a rotary cutter rotatably supported on the rotary cutter by bearing means including at least one inner roller bearing, the rollers of the inner roller bearings running in a deep radial bearing race groove in the trunnion and a deep radial bearing race groove formed in the bore of the rotary cutter and a filling opening extending generally axially in the trunnion between the inner bearing race grooves, characterized in that the outer bearing facing the drill bit body comprises a tapered roller bearing including a plurality of tapered rollers and wherein the filling opening for the rolling elements of the inner bearing is arranged radially inside the inner bearing race of the tapered rollers in the trunnion.

Abstract: A rotary drill bit having a drill bit body and at least one trunnion projecting from the drill bit body and a rotary cutter supported on at least one radial roller bearing on the trunnion. The rolling elements of the bearing are guided on at least one axial end facing the drill bit body in an outer bearing race groove incorporated in the bore of the rotary cutter. The inner bearing race groove is formed on the trunnion for the rolling elements of the radial roller bearing. At least one filling opening is provided which extends through the drill bit body and trunnion and is essentially axially oriented having one terminal end adjacent the inner bearing race groove and at least one pair of filler piece for sealing the opening. One of the filler pieces is made of an elastically compressible material.

Abstract: A rotary drill bit having a drill bit body and at least one trunnion projecting from the drill bit body and a rotary cutter supported on at least one pair of radial rolling bearings on the trunnion. The rolling elements of at least one bearing are guided on at last one axial end facing the drill bit body in an outer bearing race groove incorporated in the bore of the rotary cutter. The inner bearing groove is formed on the trunnion for the rolling elements of the radial roller bearing. A filling opening is provided for assembly of the rolling elements comprising a channel which extends through the drill bit body and trunnion and is essentially axially oriented having one terminal end adjacent the inner bearing race groove and at least one filler piece for sealing the opening. The filling opening is arranged to provide a common filling means for each radial bearing.

Abstract: A rotary drill for drilling a well in the surface of the earth the drill comprising a drill bit including an upper portion for connection to a drill string, duct means for carrying fluid to extract detritus and clear the bottom of the well and receiving means; a solid cutting head comprising a conical head portion and a stem portion, the conical head portion including holes therein and cutting elements inserted in the holes, the stem portion being received in the receiving means of the drill bit, wherein the stem and the receiving means include holding means for rotatably holding the cutting head in the drill bit; bearing means between the drill bit and the conical head; and a lubrication system interconnected between the drill bit and the cutting head.

Abstract: A rock bit for drilling hard formations has a bit body with a plurality of rolling cone cutters mounted on it for rotation with rotation of the bit body. The cutters each have a plurality of recesses in their outer surfaces and a tungsten carbide insert is interference fitted into each of said recesses. A large diameter rock bit has such inserts larger than about 3/4 inch diameter and a cavity is provided in the cylindrical base of such an insert. The cavity has a volume in the range of from about 15 to 30% of the volume of the cylindrical base and extends into the cylindrical base a distance of at least about 40% of the diameter of the base. The depth of the recess is more than half of the length of the portion of the insert that grips the recess in which it is inserted. Large savings in expensive tungsten carbide can be made without decreasing performance of the tungsten carbide inserts.