Patent attributes
An insert detachably attached to an indexable rotary cutting tool, having an upper surface having cutting edges along the ridgeline, a lower surface, side surfaces, and a center hole for a fastening screw; each cutting edge having a corner cutting edge formed in each acute corner portion, and a bottom cutting edge and a peripheral cutting edge formed along the ridgelines on both sides of the corner cutting edge; the bottom cutting edge and the peripheral cutting edge having different clearance angles; a flank of the corner cutting edge having an angle-changing surface portion having a clearance angle continuously changing in a region from the bottom cutting edge to the peripheral cutting edge; and the length of the peripheral cutting edge being restricted by a receding portion adjacent to an upper end of the peripheral cutting edge.