Abstract: A broach has a main body of a cemented carbide material. On this main body, a front grip portion, a cylindrical portion following the front grip portion and provided with a plurality of guide parts in its outer periphery, a broach cutting edge portion following an end of the cylindrical portion and having a number of cutting edges, and a cylindrical extension following the broach cutting edge portion and having a maximum outer periphery dimension to such an extent that the extension does not interfere with a work are integrally provided. On an end surface of the cylindrical extension, a load receiving shoulder is formed, which leads to a rear grip portion including a small-diameter part and is orthogonal to or inclined with respect to a broach axis. The load receiving shoulder has a sufficient area to bear a cutting load. A broaching machine grips the rear grip portion with its load receiving surface abutting against the load receiving shoulder of the cemented carbide broach.

Abstract: A broach tool for finishing a hollow hole has a number of cutting edges arranged in order of dimensions in a longitudinal direction. The cutting edges in at least a finishing portion are formed of cemented carbide. A cutting depth of each edge in a cutting direction is 5 &mgr;m to 15 &mgr;m for slots such as a spline hole and a ball groove, or 3 &mgr;m to less than 9 &mgr;m for a round broach hole. A work has the hollow hole pre-worked leaving a finish cutting allowance, and has hardness of 45 to 65 HRC (Rockwell hardness C scale) after subjected to a thermal treatment. A hollow hole cut surface is finished into the finished dimension with use of the broach tool. The broach tool has little chipping on cutting edge tips and is hardly abnormally worn and has a long life.