Abstract: A broaching cutter includes a plurality of initial cutting blade stages for cutting formation portions to be tooth body portions in internal teeth, a plurality of intermediate cutting blade stages for cutting the formation portions to be the tooth body portions further deeply, and a plurality of final cutting blade stages for cutting formation portions to be clearance portions located deeper than the tooth body portions, the initial cutting blade stages, the intermediate cutting blade stages, and the final cutting blade stages being sequentially arranged from an upstream side in a cutting direction S. Each of a pair of distal end corners of each of cutting blades in the intermediate and final cutting blade stages has a chamfered shape larger than that of a curved shape of a pair of distal end corners of each of the cutting blades in the initial cutting blade stages.

Abstract: A broaching cutter includes a plurality of initial cutting blade stages for cutting formation portions to be tooth body portions in internal teeth, a plurality of intermediate cutting blade stages for cutting the formation portions to be the tooth body portions further deeply, and a plurality of final cutting blade stages for cutting formation portions to be clearance portions located deeper than the tooth body portions, the initial cutting blade stages, the intermediate cutting blade stages, and the final cutting blade stages being sequentially arranged from an upstream side in a cutting direction S. Each of a pair of distal end corners of each of cutting blades in the intermediate and final cutting blade stages has a chamfered shape larger than that of a curved shape of a pair of distal end corners of each of the cutting blades in the initial cutting blade stages.

Abstract: A cutting tool for cutting a lead-free copper-based bearing alloy containing 75 to 95% by mass Copper(Cu):, 1 to 15% by mass Bismuth(Bi), and 1 to 10% by mass hard particles comprising metal phosphide, boride, or carbide. The Cutting tool includes a rake surface, a clearance surface, and a cutting edge formed on a line of intersection between the rake surface and the clearance surface. A tip end site including the cutting edge comprises a diamond tip, and the diamond tip comprises a sintered body formed by sintering diamond particles having an average particle diameter (D50) between 0.2 ?m and 1.6 ?m. The cross section of the cutting edge preferably has a curved surface shape with a radius of curvature between 10 ?m and 50 ?m.