Niagara Cutter N9839 High-Speed Steel End Mill, General Purpose, TiAlN Coated, 4 Flutes, Square End, 5" Cutting Length, 7/8" Cutting Diameter, 7-1/4" Overall Length Number of flutes varies; fewer flutes have more chip-carrying capacity and more flutes produce a finer finish Titanium aluminum nitride (TiAlN) coating lubricates the end mill for high-temperature stability and abrasion resistance at high cutting speeds, offering better heat resistance than TiN and TiCN coatings High-speed steel is compatible with a variety 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