Baker Hughes Corporation

Reed Tool Company

Reed Rock Bit Company

John D Parrish

Terry H Mayo

Rodney A Bellamy

A method of manufacturing a rock bit of previously formed lugs which will be welded to form a body. Initially, a shank end positioner means such as drilled holes are formed on the lug, which are then positioned on a mating receiver such as dowels in a fixture. The bearing end of the lug is clamped against a locator block to establish a predetermined relationship between the shank end and the bearing end of the lug. This relationship determines both the radial, axial and angular positions of the bearing and shank ends of the lug. Then, the faces of the lug are machined while held in this accurate aligment. When assembled and welded with similarly manufactured lugs, a bit of exceptional accuracy is produced in a cost effective manner. A slightly different position of the locator block permits the use of lugs of normal forging tolerances to be positioned to provide another location of the faces and bits of different sizes.

Rock bit manufacturing method

The present invention discloses a large diameter oil well drilling bit which utilizes a unique cast body upon which are secured a plurality of cutting assemblies comprising a leg, a bearing journal and a rolling cutter mounted on the bearing journal.

Large diameter oil well drilling bit

A rolling cutter drill bit is disclosed which utilizes a plurality of rolling cutters each rotatably mounted on a lug member having a downwardly extending bearing journal. Each bearing journal has a ball bearing race formed therein for receiving a series of ball bearings which also seat in a mating ball bearing race formed in the rotatably mounted cutter. The ball bearings are arranged to share the axial loading placed on the rolling cutter and primarily lock the cutter on the journal shaft. Each journal is further provided with a unique large thrust surface across the downward end of the bearing shaft and generally perpendicular to the radial bearing surface. The large flat perpendicular thrust surface eliminates the need for a standard pilot pin structure normally found in rolling cutter bits. The elimination of the pilot pin structure allows the radial bearing surfaces to be machined in a more economic manner and eliminates the accumulated tolerances being concentric bearing surfaces which previously contributed greatly to cocking of the cutter on the journal and the resulting high stress single point loading which occurs from the cocking action of the cutter.

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Houston, TX, United States of America

John D Parrish