Cutter insert for KEVLAR

A cutting insert, for use on a rotating holder as a countersinking tool to cut a work piece, said holder having an axis of rotation and a pocket to receive the insert, said pocket having a planar reference surface parallel to the axis of rotation, a first reference surface adjoining and perpendicular to said planar reference surface, and a second reference surface adjoining and perpendicular to said planar reference surface and adjoining and perpendicular to said first reference surface, said cutting insert comprising:

• an inside surface for engaging said planar reference surface and seating said insert in the pocket of said holder;
• a first peripheral edge, adjoining and perpendicular to said inside surface, for engaging said first reference surface and seating said insert in said pocket of said holder;
• a second peripheral edge, adjoining and perpendicular to said inside surface and perpendicular to said first peripheral edge, for engaging said second reference surface and seating said insert in said pocket of said holder;
• a third peripheral edge adjoining and perpendicular to said inside surface and perpendicular to said first peripheral edge and parallel to said second peripheral edge;
• an outside surface parallel to said inside surface and joining and perpendicular to said first peripheral edge, joining and perpendicular to said second peripheral edge and joining and perpendicular said third peripheral edge
• means for releaseably holding said insert in said pocket of said holder;
• a relief face adjoining said third peripheral edge and located between said second and said third peripheral edges, said relief face comprising a flat surface intersecting said inside surface at axial relief angle of 19 degrees plus or minus two degrees and at a radial relief angle of 23.degree. plus or minus 2.degree. ;
• a primary rake face adjoining said third peripheral edge and located between said second and said third peripheral edges, said primary rake face comprising a flat surface intersecting said outside surface at an angle of 5 degrees plus or minus two degrees;
• a chamfer cutting edge formed by the intersection of the relief face and the primary rake face, said chamfer cutting edge located 4 degrees positive to the centerline of the holder.