When polygon turning, the part and cutter head turn in the same direction. The cutter head generally rotates at twice the speed of the part, with each cutting edge turning a pair of opposite flats on the part. This means that the number of flats produced during polygon turning is twice the amount of the cutting edges. Using a polygon turning attachment or a tool spindle operating in sync, Polygon turning is used for parts made from non-ferrous metals . brass, aluminum and steel . The radial plunging procedure also allows flats being machined behind the collar. Axial, longitudinal turning is used to create long flats.