Patent ID: 7850250

Claim:
The combination comprising a tool holder having a planar forward surface and a cylindrical bore extending into a body of said tool holder, said cylindrical bore having an axis perpendicular to said forward surface, a rotatable tool having a tool body with a longitudinal axis, an enlarged cutting head and a cylindrical shank extending rearwardly of said enlarged cutting head, a hardened tip at a forward end of said enlarged cutting head, said shank joining said enlarged cutting head at an annular flange, said annular flange having a planar annular inner portion joining a forward end of said shank and a planar annular outer portion extending to a maximum diameter of said annular flange, said annular inner portion being axially forward of said annular outer portion, an annular midportion in the form of an offset extending between said planar annular inner portion and said planar annular outer portion, a wear ring around said shank, said wear ring independent of said tool holder, said wear ring having a planar forward surface, a planar rearward surface contacting said planar forward surface of said tool holder, and an outer edge joining said planar forward surface to said planar rearward surface, said planar forward surface of said wear ring including an annular inner portion spaced from said annular inner portion of said annular flange, and an annular outer portion contacting said outer portion of said annular flange wherein an open spacing remains between said annular inner portion of said planar forward surface of said wear ring and said planar annular inner portion of said annular flange.