Thread whirling is a machining process used in manufacturing to produce external threads on cylindrical parts. In this process, a cutting tool rotates around the workpiece, and the cutting edges engage with the material to form the threads. The tool moves along the length of the workpiece while simultaneously rotating, creating a helical path and producing the desired thread profile.

Thread whirling is often employed for high-precision and high-volume production of threaded components. It allows for efficient machining of long threads on slender parts and is particularly useful for producing screws, worm shaft, lead screws and other threaded elements with intricate profiles. The process is known for its accuracy and ability to achieve tight tolerances in thread dimensions.