| 摘要 |
PROBLEM TO BE SOLVED: To improve the tool lifetime while improving the cutting chip processing ability by providing a side surface of a breaker upheaved part with a part standing at an angle in a specified range. SOLUTION: A breaker upheaved part 10 is arranged so that a distance (d) from a tip of a nose part 5 to a sanding boundary of the breaker upheaved part 10 is formed at 0.3-0.7 mm in relation to the nose part 5. Cutting angleΑis set at 3-16 degree, and standing angleαof a front surface of the breaker upheaved part 10 facing to a tip of the nose part 5 is set at 20-40 degree. Cutting angle of a lateral cutting blade is set at 3-16 degree, and a side surface of the breaker upheaved part 10 is formed with a part standing at 30-60 degree. Cutting chips having a large width while being cut large is energized so as to be curled by the cutting face of the lateral cutting blade having a cutting angle, and made to collide with a side surface of the breaker upheaved part 10 stood at a large standing angle so as to be securely curled. Even if cutting depth is increased, breakdown of the breaker upheaved part 10 and clogging with cutting chips can be eliminated.
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