| 摘要 |
PURPOSE:To reduce a tool cost per cutting edge and save resources, by changing only a cutting edge of a prior-art throwaway tip to a throwaway type and by increasing the number of usable cutting edges. CONSTITUTION:A tip 12 of a short-side equilateral triangle is provided with a columnar projection 13 which is formed integral with the tip and has a chamfered end 13a. The throwaway tip including a removable cutting edge is constituted by attaching the tip 12 to the tip mounting seat 14a at each corner of a tip body 14. Since the columnar projection 13 is disposed in an axial posision of the tip 12 formed axially symmetrically with respect to each vertex of the tip 12, the tip 12 can be rotated to substitute a new cutting edge for a used worn edge. Namely because every cutting edge of the tip 12 made of rare and expensive raw materials is usable, the number of usable cutting edges can be increased, thereby reducing a tool cost per cutting edge and saving resources. |
