Patent ID: 6913426

Claim:
A throwaway insert comprising: a bottom face as a mounting face; an upper face opposing the bottom face; a side face formed between the bottom face and the upper face; and a cutting edge formed along an intersecting ridge between the upper face and the side face in a substantially arc shape such that the rotational trace of the cutting edge when being attached to a tool body in use substantially forms a partial spherical surface, wherein an undulating portion, which is formed by alternately arranged concave portions and convex portions, is provided on the upper face so as to intersect the cutting edge, and so as to provide a wavy shape to the cutting edge, wherein at least one of the concave portions is formed as a deep-concave portion which has a greater depth than that of the others, and wherein the depth of the deep-concave portion at the cutting edge, as viewed in a direction along which the concave portions and convex portions extend, while viewing the side face, is set in a range from 1.2 to 3.0 mm.