Cutting insert

Abstract

A metal cutting insert having a pair of cutting portions disposed on either side of a shank portion which also includes a clamping structure engageable by a tool holder by which the metal cutting insert is held in an operative position. Each cutting portion includes a circular cutting edge that is defined by the juncture of a circular clearance surface and a frusto-conical, positive rake surface. The cutting edge is located in a common horizontal plane. A plurality of elongate spaced apart, radially directed recesses are symmetrically spaced with respect to the cutting edge and include outer ends that merge with the frusto-conical rake surface and inner ends which merge with a plateau-like surface having an upper surface located at a level higher than the cutting edge. The plateau-like surface defines a discontinuous circular edge in the form of arcuate ridges. A plurality of chip deflectors defined in part by shallow depressions are located between the associated recesses and extend from the rake surface and merge with an associated ridge. The recesses have a longitudinal extent greater than the chip deflector such that the ridges are disposed between associated recesses. The metal cutting insert is molded from a carbide or similar material and is adapted to be used as a single use insert. At least the cutting portion of the insert is coated with titanium nitride, titanium carbo-nitride, titanium aluminum nitride or other suitable material.