Patent ID: 6676711
Filing Date: 2004-01-13
Classification: B23B,Y10T

Abstract:
A hole cutter including a cylindrical blade body with a rotational axis, wherein the blade body includes a plurality of blades and a plurality of grooves, each of the blades is arranged alternately with a corresponding one of the grooves around the rotational axis, each blade has a cutting edge formed at an end of the blade, and the cutting edge of each blade includes:an outer cutting edge, which is located closer to the outer circumference of the blade body and extends substantially in a radial direction of the blade body; an inner cutting edge, which is located closer to the inner circumference of the blade body and extends substantially in the radial direction of the blade body; and a stepped cutting edge, which is located between the outer cutting edge and the inner cutting edge and extends substantially in a circumferential direction of the blade body; wherein the outer cutting edge of each blade has a point located at a radial outer position of the outer cutting edge, the inner cutting edge of each blade has a point between the inner cutting edge and the stepped cutting edge, the heights of the points of the inner cutting edges with respect to a predetermined reference plane perpendicular to the rotational axis are substantially equal for all blades, and the heights of the points of the outer cutting edges with respect to the reference plane are different among the blades.