The process begins with a flat piece of metal or a metal cylinder. It is cut to a specific size based on the size of the finished part. A form is used to create the internal shape of the spun metal part. The form is often made of aluminum or hardened steel. Metal spinning used to be used for creating prototypes and where only a few parts needed to be made. With the introduction of automatic lathes, metal spinning can be used to create a larger number of parts inexpensively. 