ROTATIVELY MOUNTING CUTTERS ON A DRILL BIT

摘要

A method and apparatus are disclosed for rotatively mounting cutters on a drill bit. A bore is provided either directly in the drill bit or in a sleeve which is mounted on the drill bit. The bore includes a female screw thread, a circumferential groove, and one or more bearing surfaces. A cutter with a hardened table has a generally cylindrical body with a male screw thread, a circumferential groove, and one or more bearing surfaces. The cutter is engaged with the threads of the bore and then advanced until the male screw threads pass beyond the female screw threads. When the cutter is fully installed, the circumferential grooves provide relief for the screw threads so that the cutter can freely rotate within the bore.

主权项

1. A cutter for a drill bit for drilling a wellbore in an earthen formation comprising:
a generally cylindrical body defining a shaft extending between a face end and a root end; a hardened table disposed at said face end; a male screw thread formed along the shaft; and a circumferential groove formed along the shaft between said face end and said male screw thread.