Uncoated High-Speed Steel—Use uncoated end mills for general purpose milling and short production runs. They stay sharper than coated end mills when used on soft materials like aluminum, leaving a better finish.

Titanium Nitride (TiN)-Coated High-Speed Steel—Titanium nitride (TiN)-coated end mills create less friction than uncoated end mills, which means they last longer when run at similar speeds. Use coated end mills for demanding, high-speed jobs in hard material as well as for longer production runs. The coating reduces friction and vibration as they’re used, making them more wear resistant than uncoated end mills.

Aluminum Titanium Nitride (ALTiN)-Coated High-Speed Steel—Aluminum titanium nitride (AlTiN)-coated end mills dissipate heat better than other end mills, especially at high speeds. At high temperatures, the coating creates a layer of aluminum oxide that transfers heat to the chips, keeping the tool cool, even when used without lubrication. Use coated end mills for demanding, high-speed jobs in hard material as well as for longer production runs. The coating reduces friction and vibration as they’re used, making them more wear resistant than uncoated end mills.