Union Butterfield 5210031 Cobalt Steel Square Nose End Mill, Inch, Weldon Shank, Uncoated (Bright) Finish, Roughing Cut, 4 Flutes, 3.25" Overall Length, 7/16" Cutting Diameter, 1/2" Shank Diameter Roughing end mills (also called rougher) have chip-breaking cutting edges that remove material in less time than conventional end mills 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