Cutting insert having two upper cutting edges and a lower central protuberance with four abutment walls defining an imaginary quadrilateral, and rotary cutting tool

摘要

A cutting insert has opposing upper and lower surfaces interconnected by a peripheral side surface, an insert axis passing through the upper and lower surfaces, and first and second upper cutting edges formed at the intersection of the upper surface and the peripheral side surface. A lower central protuberance having first, second, third and fourth abutment walls extends downwardly from the lower surface. In a cross-section taken in a first horizontal plane perpendicular to the insert axis and intersecting the lower central protuberance, the first, second, third and fourth abutment walls define an imaginary quadrilateral having diagonally opposing first and third internal angles and diagonally opposing second and fourth internal angles. The first and third internal angles are equal to each other, and the second and fourth internal angles are not equal to each other. Two cutting inserts are removably secured in a rotary cutting tool.