Patent ID: 8858130

Claim:
A toolholder system for cutting a workpiece, wherein there is relative rotation between the toolholder and the workpiece, wherein the toolholder system is comprised of: a) at least one circular cutting insert having: 1) a front face, an opposing back face, a side wall therebetween and a central longitudinal axis therethrough; 2) a front cutting edge at the intersection of the sidewall and the front face; 3) a back cutting edge at the intersection of the sidewall and the back face; 4) a plurality of front positioning segments on the front face, wherein the front segments have radial centerlines and, wherein the centerlines of adjacent segments define evenly spaced radial angles RA about the central longitudinal axis for indexing the insert within a toolholder, wherein the front positioning segments define a front pattern; 5) a plurality of back positioning segments on the back face, wherein the back segments have radial centerlines and, wherein the radial centerlines of adjacent segments define evenly spaced radial angles RB about the central longitudinal axis for indexing the insert within a toolholder, wherein the back positioning segments define a back pattern identical to that of the front pattern; and 6) wherein the radial centerlines of the back positioning segments, when projected along the central longitudinal axis through the body onto the front face, bisect the radial angles RA defining the front positioning segments; and b) a toolholder having at least one seat securably holding the at least one circular cutting insert non-rotatable about the insert central longitudinal axis, wherein each of the at least one seats includes a bottom wall for engaging one of the front face and the back face of an insert, wherein the bottom wall further includes a plurality of receiving segments positioned upon the bottom wall in the same pattern as the front face and the back face and wherein the at least one cutting insert is indexably secured to the toolholder such that during a cutting operation, when mounted with the front face exposed, a portion of the front face cutting edge is available to the workpiece and when the same insert is inverted with the back face exposed, a portion of the back face cutting edge is available to the workpiece, wherein the front face portions and the back face portions available to the workpiece are always radially shifted from one another.