With larger diameters than end mills, these cutters remove greater amounts of material to create a smooth, flat channel in the face of a plate, bar, or other wide workpiece. Compared to fly cutters, they’re more rigid, which makes for a better finish. Also known as shell cutters. Cutters with fewer teeth provide better chip clearance for high-volume, high-speed cuts. Those with more teeth provide a finer finish and generate less vibration at high speeds.

High-speed steel cutters are good for general purpose milling in most materials including aluminum brass, bronze, and steel. Use coated cutters 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 cutters.

Aluminum-titanium-nitride (AlTiN) coated cutters dissipate heat better than other cutters, 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.