Niagara Cutter N45320 High-Speed Steel End Mill, General Purpose, TiN Coated, 4 Flutes, Double Square End, 1-7/8" Cutting Length, 1" Cutting Diameter Four flutes produce a better finish than fewer flutes Double-end end mills have cutting edges on both ends for longer tool life Titanium nitride (TiN) is a general-purpose coating that combines high-temperature resistance and increased hardness compared to uncoated end mills High-speed steel is compatible with a variety of materials Square nose end mills (also called square end) create sharp, unrounded cuts