Trigon (W) milling inserts have a modified triangular shape that has three cutting points with 80° nose angles. Also called trigonal inserts, they have a stronger cutting edge than triangle inserts but make shallower cuts. They are used for roughing and finishing cuts in turn milling and facing applications. 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. 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.