Patent ID: 7204663

Claim:
An end mill comprising: a shank portion being configured to be gripped in a tool; a cutting portion having a central longitudinal axis; said cutting portion comprising: a central core portion; a first cutting section being configured to perform a finishing machining; said first cutting section being connected to said shank portion; said first cutting section comprising: a plurality of cutting edges being disposed to project from said central core portion; and a plurality of flutes disposed adjacent their corresponding cutting edges; a second cutting section being configured to perform a rough machining; said second cutting section being connected to said first cutting section; said first cutting section being disposed between said shank portion and said second cutting section along the central longitudinal axis; said second cutting section comprising: a plurality of cutting edges being disposed to project from said central core portion; and a plurality of flutes disposed adjacent their corresponding cutting edge portions; each of said plurality of cutting edges of said first cutting section being disposed a first distance from said central longitudinal axis; each of said plurality of cutting edges of said second cutting section being disposed a second distance from said central longitudinal axis; said first distance being greater than said second distance; said first cutting section having a larger number of cutting edges and flutes than said second cutting section; said flutes in said second cutting section having a total cross-sectional area being sufficiently large to permit removal of chips during rough machining; said flutes in said first cutting section having a total cross-sectional area being sufficiently large to permit removal of chips during finishing machining; and the total cross-sectional area of said flutes in said second cutting section being substantially greater than the total cross-sectional area of said flutes in said first cutting section.