Niagara Cutter N85650 Carbide Square Nose End Mill, Double End, Weldon Shank, TiAlN Finish, Roughing and Finishing Cut, 30 Degree Helix, 4 Flutes, 4" OAL, 0.500" Cut Diameter, 0.500" Shank Diameter Four flutes produce a better finish than fewer flutes Double-end square nose end mills create sharp, unrounded cuts and have cutting edges on both ends for longer tool life 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 Carbide can run at higher speeds than high-speed steel, resisting abrasion and high cutting temperatures Center-cutting design allows the end mill to plunge into material like a drill bit while also performing conventional surface milling