Roughing ball end mills remove large amounts of material from a workpiece more quickly than finishing ball end mills. Sometimes called corn cobs and hog mills, roughing end mills have a tooth design that minimizes vibration during milling tasks but leaves a rough finish on the workpiece. Cobalt end mills can be used at higher speeds and are harder and more wear-resistant than high-speed steel end mills. Also known as ball-nose end mills, ball end mills have a rounded nose and create a round-bottomed groove in milling tasks. They are rotated against a workpiece to make round-bottomed slots and pockets or mill complex shapes without sharp corners.