The concept of metal spinning
With the help of a tempered steel roll, a round slab of metal is pressed on top of a rotating mould in the form of the desired object
Usually, the moulds are made from ordinary untempered steel. To obtain better surface quality and hardness it is often good to temper the tools used and it is almost always necessary temper tools made from stainless steel. It is possible, however, to make the tools of a model series out of even wood.
As the picture shows, objects of many sizes and forms can be made by metal spinning.