Abstract: A well drilling bit comprises a bit body with a centralized portion and a plurality of radially and circumferentially spaced legs depending longitudinally therefrom. A respective cutter body is rotatably mounted on the free end of each leg with bearing means. The bit body has a respective lubricant passage communicating with each bearing and a respective upwardly opening lubricant reservoir recess, the recess also communicating with a respective vent port opening downwardly through the bit body. A respective lubricating mechanism is disclosed in each lubricant reservoir recess, and each such mechanism comprises an elastomeric pressure compensating diaphragm extending across the recess and sealed with respect thereto, dividing the recess into a lower portion communicating with the vent port and an upper portion communicating with the lubricant passage.

Abstract: An improved pressure compensator of the top-vented type for a roller cone drill bit comprises an elastomeric compensator diaphragm having an annular, peripheral, radially outwardly extending flange. An annular, axially acting compression spring is at least partially imbedded in the flange, elastomeric material of the flange at least partially underlying and overlying the spring for sealing engagement, respectively, with an axially facing shoulder in a recess in the bit body and a cap forming part of the assembly. The cap is disposed above the flange in the bit recess, and has a lower end surface for sealing abutment with the flange. The cap also has a vent communicating a zone above the diaphragm, in the recess, with the exterior of the bit. A retainer is positioned to hold the cap in the recess, thereby also retaining the diaphragm in the recess, and compressing the spring sufficiently to cause sealing engagement on both sides of the flange, but not beyond the elastic limit of the spring.

Abstract: A method of manufacturing a roller cone type drill bit, or main body thereof, includes forging a monolithic main body forging comprising a shank blank extending longitudinally at one end and a plurality of circumferentially spaced leg stubs at the other end; turning the shank blank to form a threaded section; rotatably mounting a respective roller cone on each of a plurality of journal members, each journal member being carried at one end of a respective leg extension; and welding a respective one of the leg extensions to each of the leg stubs. The main body is forged with its longitudinal centerline perpendicular to its flash line, the latter being located well inward of the leg end of the forging.