Abstract: An earth boring bit having an improved two piece bearing construction using an internally tapered and threaded, cantilevered bearing lug extending obliquely inwardly and downwardly from a leg carried by the body of the bit. An internally tapered and threaded bearing sleeve is made up on the lug, and includes a mouth that engages a shoulder on a base region of the bearing lug. The mouth of the sleeve has a minimum radial thickness such that the sleeve may be made up to a selected minimum torque. The bearing sleeve has a length greater than that of the treaded portion to define a thick walled inner end region to receive a resilient retainer ring in a groove that provides a minimum section over the threads on the interior of the sleeve. The sleeve is boronized to achieve wear resistance in a manner that does not substantially reduce strength.

Abstract: A method for shanking a rock bit utilizing a shank locator and a cone locator, each with tapered surfaces to engage respectively the tail stock of a lathe and the cones of a rock bit, to accurately align the body and the cones of the bit concentric with the design centerline of the bit. The lathe and cone locators each have interior conical surfaces to assure accurate, coaxial alignment of the shank end and the cone end of the bit. A compensating chuck is used to grip the cone end of the bit body and firmly hold the normally uneven surfaces while the threads are being machined.

Abstract: A method and a clamping assembly for securing rock bit sections during welding. The assembly has a chuck jaw that is supported by metal rods, which give the assembly enough resiliency to conform to the shape of the rock bit and which keep the chuck jaw parallel to the base so that the point of engagement between the chuck jaw and the rock bit section remains constant.

Abstract: A method of assembling sections of an earth boring bit for welding has features to assure precise bit geometry. The method includes a step of providing a hole in each bit section at the centerline of the 120 degree faces on the interiors of the sections. A triad is constructed for use in assembly and consists of three pins joined together on one end, each having an axis 120 degrees apart from the other axes of the pins. The triad is positioned in the holes in the 120 degree faces when the three sections of the bit are brought together. The shank ends of the sections have holes for receiving dowels located in the welding fixture. Once the sections are positioned and pinned against movement at the shank ends and at the triad, the sections are clamped, then welded.

Abstract: Following is disclosed an improved split-type stop ring having two separable body portions forming an annular composite body with passage means useful with a fluid operated, percussion type drill motor for retaining a drill bit and enabling the by-pass of fluid when the bit is suspended above the bottom of a borehole. Fluid by-pass enables the continued flow of fluid to clean the borehole bottom while stopping the otherwise damaging piston-hammer reciprocation when the bit is suspended above bottom.