Patent ID: 7367754

Claim:
A rotary cutting tool, comprising: a substantially cylindrical main body having a shank end and a cutting end formed integrally opposite the shank end, the main body having a longitudinal axis of rotation; a pair of flutes comprising a first flute and a second flute formed on opposite sides of the main body, wherein each of the pair of flutes extends continuously from the cutting end towards the shank end, each of the pair of flutes defining a helical cutting edge having a helix angle with respect to the longitudinal axis of rotation of the main body; wherein the pair of flutes are symmetrical and have the same helix angle; a third flute formed on one side of the main body between the pair of flutes, the third flute defining a helical cutting edge having a helix angle that is different than the helix angle of the pair of flutes; and a fourth flute formed on the other side of the main body, between the pair of flutes and generally opposite the third flute, the fourth flute defining a helical cutting edge having a helix angle that is different than the helix angle of the pair of flutes and different than the helix angle of the third flute.