| 摘要 |
In order to obtain a borer with a groove with a cutting angle which is greater than the cutting angle of conventional borers and a clearance angle which is smaller than the clearance angle of conventional borers, a torsion force is applied to a borer blank having a polygonal cross-section in the vicinity of its edges whilst deforming the angular end in the direction of the torsion. The device comprises a chuck (5) holding the base of the borer blank (1) and a vice (7) fitted with several jaws capable of compressing the sides of the blank (1), the chuck (5) and the vice being capable of moving away from each other by revolving with respect to each other. The jaws are mounted so as to be able to advance and retract along the thickness of the blank (1). <IMAGE> |
