These end mills have either a neck or shank that’s extended and has a reduced diameter—this prevents them from rubbing against your workpiece when deep milling. Variable spacing between the flutes reduces vibration, allowing the end mills to provide fast cuts, smooth finishes, and long tool life on hard materials. Often used for slotting and pocketing cuts in mold and die making, they have a 90° profile and rounded corners, which reduce flute breakage and chipping. Also known as corner radius end mills.

Made of solid carbide, these end mills are harder, stronger, and more wear resistant than high-speed steel and cobalt steel for the longest life and best finish on hard material. Their extreme hardness means they are brittle, so a highly rigid setup, such as a CNC machine, is necessary to prevent the end mill from breaking.

An aluminum titanium nitride (AlTiN) coating allows them to 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. This makes these good for aggressive machining while roughing or making interrupted cuts.

End mills with fewer flutes provide better chip clearance for high-volume, high-speed plunge, slotting, and roughing cuts; end mills with more flutes provide a finer finish and operate with less vibration when run at high speeds.