Niagara Cutter N52121 Cobalt Steel Square Nose End Mill, Inch, Weldon Shank, Uncoated (Bright) Finish, Finishing Cut, 30 Degree Helix, 4 Flutes, 2.5" Overall Length, 0.375" Cutting Diameter, 0.375" Shank Diameter Number of flutes varies; fewer flutes have more chip-carrying capacity and more flutes produce a finer finish Cobalt steel resists abrasion and high cutting temperatures, and has higher feed rates than high-speed steel Uncoated (bright) tools have no additional surface treatment or coating for use on a broad range of materials Square nose end mills (also called square end) create sharp, unrounded cuts Center-cutting design allows the end mill to plunge into material like a drill bit while also performing conventional surface milling