Patent ID: 8038514

Claim:
A milling tool including a cup-shaped base, and abrasive grains brazed on an end surface of the base, a groove being formed at a boundary between an outer portion comprised of a portion of the end surface of the base closer to an outer edge of the base, and an inner portion comprised of a portion of the end surface of the base closer to an inner edge, the inner portion having a planar surface higher than a planar surface of the outer portion, the outer portion having an outermost edge formed inclined or rounded, characterized in the abrasive-grain clusters are located at the outermost edge with a predetermined space therebetween, each of the abrasive-grain clusters being comprised of 5 to 8 abrasive grains having an almost same diameter, and being positioned substantially on a circumference of a common circle at an almost constant space from adjacent ones, and abrasive grains are not arranged within the common circle defined by abrasive grains of which the abrasive-grain cluster is comprised.