Cutting tool insert with chip breaker

Claim 1

A cutting tool insert having a chip breaker arrangement, the cutting tool insert being polygonally shaped having top and bottom surfaces spaced from each other, side surfaces joining the said top and bottom surfaces, cutting edges forming a substantially unbroken line at the junction of the said side surfaces and the said top and bottom surfaces, a chip breaker groove in at least one of the said top and bottom surfaces being shaped in such a manner that any normally directed section plane intersects the groove in three substantially rectilinear portions, the groove being separated from the cutting edges by cutting edge land surfaces and being positioned to shape the chip after cutting and without the further cutting thereof, said groove having an edge constituted by successive, substantially continuous, linear groove edge portions which respectively define between them and the cutting edge, successive land surface regions of successively increased and reduced widths, at least five such successive land surface regions being included in each land surface.