ROTARY CUTTING TOOL AND THROW AWAY TIP

摘要

PROBLEM TO BE SOLVED: To provide a rotary cutting tool by which cutting of an end surface and cutting of an outside diameter can be performed by a single unit, and provide a throw away tip whose edge strength can be secured while further reducing cutting resistance by being used in such a cutting tool. SOLUTION: A disk shaped tip 24 where a cutting edge 27 is formed in a crossing ridgeline part between a circular surface 25 and a circumferential surface 26, is rotatably installed around its central axis on the tip of a cutting tool main body 21 arranged so as to extend along a reference surface P. A front rake angleαand a lateral rake angleβto the reference surface P of the cutting edge 27 of this tip 24 are respectively set in a range of (-) 10 deg. to (-) 45 deg.. A breaker having a bottom surface inclining so as to gradually sink as it proceeds to its inner peripheral side is formed on the circular surface 25, and an inclined face 30 gradually inclining toward the inner peripheral side as it proceeds to the side of this circular surface 25 is formed on the circular surface 25 side of the circumferential surface 26.