| 摘要 |
A rake face (12) is formed on the both sides of an insert main body facing outside in the thickness direction thereof to make a pair, a cutting edge (14) is arranged on each side which constitutes an outer periphery of the rake face (12), the cutting edge (14) is provided with a major cutting edge (18A) and a minor cutting edge (18B) A connection part (20) formed in a concave curved shape is formed on the insert main body over the entire thickness direction of the insert main body. Of the pair of rake faces (12), each cutting edge (14) on the outer periphery of the first rake face (12A) and each cutting edge (14) on the outer periphery of the second rake face (12B) have rotation symmetry with each other. |
