Diamond-shape milling inserts have four sides of equal length and two acute (less than 90°) cutting points at opposite corners. Also known as rhombic inserts, they are used for circular, turn, shoulder, and face milling. These indexable inserts mount to a compatible toolholder, which attaches to a milling machine. They can be rotated (indexed) to expose a fresh cutting edge when the old one dulls. They can be replaced with new inserts of the same type or different types without removing the toolholder from the machine. Diamond milling inserts are differentiated by their nose angle measurements. Narrow cutting-point nose angles provide small cutting depths and decreased vibration while wide cutting-point nose angles provide large cutting depths and increased cutting force. Indexable milling tools require fewer tool changes than solid tools in high-volume metalworking and fabrication applications with high speeds, high feeds, and difficult-to-machine materials.