When one end wears out, switch to the opposite end for two times the life of a standard high-speed steel end mill. Made of high-speed steel, these end mills are for general purpose milling in most material, such as aluminum, brass, bronze, iron, and steel. Their square ends make them good for milling square slots, pockets, and edges. All are center cutting, allowing plunge cuts into a surface.

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.

Use uncoated end mills for general purpose milling and short production runs. Use titanium-nitride (TiN) coated end mills for demanding, high-speed jobs in hard material as well as for longer production runs. They’re more wear resistant than uncoated end mills, which means they last longer when run at similar speeds.