| 摘要 |
An insert for a drill in which one of the cutting edges respectively formed at four side ridge portions of a rake face of a square flat plate-shaped insert body is made to protrude toward the tip of the drill body of the indexable insert drill while being detachably attached is provided. Each of the cutting edges has a corner cutting edge located at a corner of the rake face, and a major cutting edge and a wiper edge which extend substantially toward one peripheral direction of the rake face from a corner cutting edge. The major cutting edge has a first major cutting edge portion which has a convexly curved shape and extends from the corner cutting edge, and a second major cutting edge portion which smoothly touches the first major cutting edge portion and extends linearly, as seen from a direction facing the rake face. The wiper edge has a straight shape intersecting the second major cutting edge portion at an obtuse angle.
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