Patent ID: 7832966

Claim:
A generally cylindrical cutting tool for making a flat bottom hole, said tool having a longitudinal central axis, and a cutting end, said cutting end comprising: a) a first peak surface and a second peak surface intersecting at and generally adjacent to said central axis and forming a chisel edge, wherein a bisector line extends radially through the central axis perpendicular to the chisel edge and defines a first tool half on one side of the bisector line and a second tool half on the other side of the bisector line, and b) wherein each tool half has a first curvilinear cutting edge portion formed by the intersection of a first thinning surface and one peak surface, said first curvilinear cutting edge portion extending radially from said chisel edge, and a second cutting edge portion extending radially outward from said first cutting edge portion wherein the second cutting edge portion is perpendicular to the longitudinal axis, and wherein when viewed from the cutting end, said chisel edge blends to form a smooth transition with said first curvilinear cutting edge portion.