Lead screws that are required only in small numbers are produced by whirling. This is a machining process in which a rotary tool chuck rotates around the unfinished rod. As it turns, the chuck also moves along the rod, so that the tool describes a spiral path around the rod to cut the thread.
For thread whirling, a whirling unit drive that can be operated on various machining centres is normally used. Whirling is used mainly for soft machining in the production of trapezoidal screw drives.
Advantages of the whirling method: