Niagara Cutter N72400 Cobalt Steel End Mill, Non Center Cut Rougher, TiN Coated, 6 Flutes, Chamfer End, 4" Cutting Length, 1-1/4" Cutting Diameter Roughing end mills have chip-breaking cutting edges that remove material in less time than conventional end mills Coarse-pitch tooth design is suitable for machining mild and cold-rolled steels Titanium nitride (TiN) is a general-purpose coating that combines high-temperature resistance and increased hardness compared to uncoated end mills Square end creates sharp, unrounded cuts and has a corner chamfer to strengthen the cutting edges Number of flutes varies by diameter for optimum feed and cut rate