Patent ID: 8601908
Filing Date: 2013-12-10
Classification: E21B,Y10T

Abstract:
1. A method of axial assembly of a rotating cone drill bit having a plurality of cone-leg assemblies and a one piece bit body, comprising: axially assembling a plurality of cone-leg assemblies into a bit body, wherein each cone-leg assembly comprises a leg and a cone; rotating the cones on their respective cone-leg assemblies to predetermined orientations such that cutting structures of one of the cone-leg assemblies are clear from cutting structures of neighboring cone-leg assemblies; and installing the plurality of the cone-leg assemblies into the bit body in a predetermined sequence such that the respective cutting structures of the plurality of cone-leg assemblies intermesh with each other, wherein assembling the plurality of cone-leg assemblies comprises: thermally fitting and mechanically fixing a seal riser bushing to a journal of the leg; cutting a relief portion with an increased inner diameter in the bushing through a weld access aperture on an outer leg shirttail portion; finishing an outer diameter of the bushing as necessary; disposing a retention segment into a groove defined in the journal, the retention segment having a stepped shoulder on one side, the retention segment being oriented when disposed into the groove in the journal to position the shoulder away from the weld access aperture and to provide a gap between the shoulder and adjacent surface of the groove as a weld relief space; installing an O-ring seal within an O-ring gland defined in the base of the cone; disposing the cone over the journal and pressing the O-ring seal of the cone onto the seal riser bushing; welding the retention segment to the cone using an energy beam through the weld access aperture while rotating the cone and the retention segment together about the journal; and press fitting a hollow step pin through the weld access aperture into a beam bore and into the seal riser bushing to mechanically secure the seal riser bushing to the journal and fixing the step pin in place.