LOW PROJECTION INSERTS FOR ROCK BITS

摘要

An earth boring bit has an outer row of inserts located within extra deep holes. Each of the holes has a cylindrical sidewall with a depth greater than the length of the barrel of the insert mounted within. The difference in depth is at least equal to a distorted entry zone in the hole. A portion of the sidewall that includes the entry zone surrounds the cutting end, reducing the projection of the cutting end from the land.