| 摘要 |
PROBLEM TO BE SOLVED: To provide a throw-away tip small in cutting resistance and capable of stably providing a chip deforming effect. SOLUTION: An arc-shaped recessed part 25 is provided generally at the center part of a cutting blade ridge part 15a of an end cutting edge 15 so as to lower a cutting face 16, and a recessed groove 26 extending rearward in a same arc-shape continuously from the recessed part 25 is provided in the cutting face 16. In a cutting-off operation, chips are drawn and deformed so that the lateral sectional shape thereof is projected downward according to the end cutting edge 15, and exhausted rearward along the recessed groove 26 in the cutting face. When the deformation is not provided by the pressing by a projected part provided on the conventional cutting face, a cutting resistance is small, and the chips are deformed irrespective of the vertical feed speed of the tip. |
