| 摘要 |
PURPOSE:To enable a tool, which enables high accurate cutting to be performed suppressing a change of resistance of cutting with no overcutting, to be mounted with no deformation and no residual cutting by fixing the tool, having an edge part with an included angle and a flat edge part without an included angle, to a holder from a long groove side. CONSTITUTION:A broach 2, providing an edge area C without an included angle, eliminates an overcutting area X when the broach 2 is clearly extracted. While the broach, simultaneously providing an edge part area D with an included angle and an area C serving as the flat edge part without an included angle in one edge, performs roughing by the edge part D of small resistance of cutting and decreases a cutting margin by the edge part C, enabling stable cutting of small resistance to be performed. Next the broach 2, when it cuts an asymmetric groove, is tightened to be fixed to a broach holder 1 by a screw thread 9 from a delivery hole side of the longer groove, cutting the groove having an asymmetric shape. In this way, closely attaching a thick line part 2b, the broach 2, effectively preventing its deformation, enables the asymmetric groove to be finished with no residual cutting.
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