Rip Cutting Tools 5/16 4-Flute SE AlTiN HP Carbide End Mill R155-0312HP, Features High Performance, 4-Flute, 38-Degree Helix, Variable Index, Eccentric Relief, Hyperlox Coating, Center Cutting, Made in the USA, Specs: Cutting Diameter: 5/16" (0.312), Length of Cut: 3/4, Shank Diameter: 5/16, Overall Length: 2-1/2, Number of Flutes: 4, Material Base: Carbide, Coating: Hyperlox ALTiN, Helix: 38-Degree, Variable Index (Unequal Helix) reduces chatter and harmonics, Center Cutting, Ecentric Relief, HYPERLOX coating for cast iron and steels up 60HRC. HYPERLOX, the universal solution for all types of cast iron and steel up to 60HRC, is AlTiN-based. The high content of aluminum results in high hardness. The smooth and droplet-free surface and the excellent adhesion of the coating make HYPERLOX perfect for end mills, also increase tool life and productivity.