Patent ID: 8414228

Claim:
A method of forming a rotary cutting tool comprising: providing a body having a cutting portion and a shank portion; a plurality of diametrically-opposed helical flutes formed in the cutting portion of the body, where adjacent helical flutes form an index angle therebetween in each radial plane along the axial length of the flutes; and a plurality of peripheral cutting edges formed along an intersection of a circumferential surface of the cutting portion of the body and a portion of an inner surface of a respective one of the helical flutes facing in a direction of rotation of the body, each peripheral cutting edge having a radial rake angle; forming the index angle between at least two adjacent helical flutes different from the index angle between at least one other pair of adjacent helical flutes in at least one of the radial planes; forming the radial rake angle of at least one peripheral cutting edge different from the radial rake angle of another peripheral cutting edge of a different helical flute; and forming a blended gash from an axial tangent point toward a radial tangent point.