| 摘要 |
PURPOSE:To accurately provide the peripheral part of a workpiece with a spiral groove combined with a thread having the same length as the tip train of a cutting tool, by providing the peripheral part of the tool with numerous tips in such a manner that n tips are located at equal intervals in the circumferential direction and sequentially shifted by 1/n of a pitch in the axial direction. CONSTITUTION:A cutting tool 10 has numerous cutting trips 13 on the peripheral part and has a jagged cross section. The outer edge of each tip 13 is nearly straight. A workpiece 14 is cut by the tool 10. The workpiece 14 is a round bar whose diameter is one-tenth of that of the tool 10. The workpiece and the tool are rotated in directions as shown by arrows in the drawing. When the tool 10 is fed by a prescribed quantily toward the center of the workpiece 14, the peripheral part of the workpiece is provided with a V-groove having the same sectional form as the tip 13. |
