| 摘要 |
PURPOSE:To protect the cutting edge of a tool from damage and enhance the boring property of the tool, by providing a recess-like curved cutting edge in the central portion of the tool to effectually perform cutting at the central portion around the zero-revolution-speed center of rotation of the tool and prevent chips from melt-clinging thereto. CONSTITUTION:A throwaway tip 2 has lower cutting edges 10, outer cutting edges 10a, and recesses 23, 231 having cutting edges 24, and is removably secured in the notch 11 of the shank 1 of a tool by a clamping screw 3. Since a concave cutting portion is provided at the axis 13 of the tool shank and the cutting edge 24 is located in a range of distance of 0.1-3.0mm. from the center of rotation of the tool, around the center, chips are thin and are broken before being discharged. Furthermore, the chips are prevented from melt-clinging to the tool, so that its cutting efficiency is improved. |
