Abstract: A drilling member for use in a drilling system, such as for drilling a large diameter subterranean hole or for removing rock at the earth's surface, in which the system employs a cutting head rotated about an axis and mounted for movement into a rock face, the cutting head having a plurality of drilling members, each of which has a truncated conical external surface rotated about the conical axis thereof, and a plurality of spaced-apart rows of indentors secured to the drilling member conical surface, the indentors being adapted to penetrate into the rock face a distance P, and wherein the indentors are spaced a distance not greater than 7 P apart.