CUTTING CONFIGURATION FOR A GAGE-TO-SHOULDER TRANSITION AND FACE PATTERN

摘要

Shortening of the bit life and premature failure of cutting elements on a rotating bit near or at the gage of the bit can be avoided by disposition of the cutting elements at or below a key level on the shoulder-to-gage transition. A first tooth is placed on the shoulder of a rotating bit at the key level. The key level is defined as that point on the shoulder of the rotating bit at which a tooth extends radially from the axis of the rotating bit by a distance substantially equal to the diameter of the bore drilled by the rotating bit as also defined by the gage diameter of the rotating bit. Below the key level the teeth are set on the pads in a staggered pattern that serve to increase effective cutting element concentration. The staggered pattern is repeated within a pad and between pads in selected areas. Distinguishable cutting elements are alternated within the pattern.