Rock bit with diamond reamer to maintain gage

摘要

A rock drill bit comprises a bit body and at least one rolling cone cutter mounted on the bit body, the rolling cone cutter comprising a plurality of tungsten carbide inserts including a plurality of gage inserts for drilling adjacent the peripheral wall of the hole being drilled. At least one diamond cutter protrudes from the bit body to provide a cutting edge substantially on the gage diameter of the rock bit so that such a diamond insert can engage the peripheral wall of the hole being drilled, thereby maintaining the hole gage. Each diamond cutter comprises a carbide slug inserted in the bit body and a diamond plate bonded to the slug. Such diamond cutters are on a peripheral portion of the bit body above the cutter cones.