TWIST DRILL FOR CUTTING STAINLESS STEEL

摘要

PROBLEM TO BE SOLVED: To provide a twist drill for cutting stainless steel with excellent durability by adopting a tool profile of a sharper edge when drilling a comparatively ductile material to be cut such as stainless steel and adopting a shape without applying load to a drill main body in a high speed cutting of 25 m or more. SOLUTION: This coated cemented carbide stainless steel twist drill is constituted of a helix angle: 30 to 45 deg. and a curvature of an edge groove bottom part continuous to a cutting face: 0.4 to 1.0 of a drill diameter and a groove width ratio: 50 to 70% in a cross section diagram perpendicular to the axis.