Patent ID: 8449546

Claim:
A set of at least three cutters, each of the at least three cutters comprising: a cylindrical cutter shank with a cylindrical wall and an inner circumferential inner surface, said cylindrical wall having a continuous outer cylindrical wall surface and a longitudinal axis, said outer cylindrical wall surface defining a plurality of outer radial extents and a plurality of inner radial extents at a distal end of said shank, said outer radial extents defining a plurality of teeth of said cylindrical wall, said outer radial extents and said inner radial extents defining a plurality of grooves in said cylindrical wall, each of said grooves being located between one of said outer radial extents and another one of said outer radial extents, each of said outer radial extents being located at a position that is radially outward of one or more of said inner radial extents, each of said outer radial extents extending from an outer radial extent position to said distal end, said outer radial extent position being located at a spaced location from said distal end, each of said inner radial extents extending from an inner radial extent position to said distal end, said inner radial position being located at a spaced location from said distal end, wherein a thickness of each of said inner radial extents decreases from said inner radial extent position to said distal end with respect to the longitudinal axis and a width of each of said outer radial extents decreases from said outer radial extent position to said distal end with respect to the longitudinal axis, whereby a depth of said grooves increases towards the distal end with respect to the longitudinal axis and a distance between each of said outer radial extents and another one of said outer radial extents increases from said outer radial extent position to said distal end, wherein a first cutter has an external diameter that corresponds at most to an internal diameter of a next larger second cutter and the second cutter has an external diameter that corresponds at most to an internal diameter of a further larger third cutter whereby the cutters can be pushed one into the other.