Due to the nature of the metal spinning process, its products are limited to those with concentric, axially symmetric shapes. Examples of shapes easily formed through spinning include hemispheres, cones, funnels, flanged covers, parabolas, stepped parts and dished heads. Additionally, the size of the available metal spinning equipment limits the maximum practical diameter of the components produced.
Metal spinning, whether manual or automated, requires component-specific tools; that is, the manufacturer must purchase or fashion spinning tools exactly suited to the desired geometry. Rollers and spoons -- tools made of hardened steel -- are designed for general use, while mandrels produce specific shapes. From an economic viewpoint, this makes it impractical for a manufacturer to produce low volumes of a component with a unique geometry.
Cracks and dents in the component during production are irreparable for all practical purposes. Small irregularities and minor damages to a blank or an unfinished piece means immediate scrapping, as a repair is not a cost-effective solution. During spinning, the metal piece could also undergo an undesirable hardening. It would then have to go through heat treatment before the shaping process can proceed properly.
Manual spinning, though simpler, faster, and cheaper by an order of magnitude than spinning with a computer-numerically-controlled (CNC) lathe, still comes with a few disadvantages. Manual spinning requires that operators have a high level of skill as well as a fair amount of strength, as the process is physically demanding. Also, compared to similar metal-shaping techniques -- such as press forming -- manual metal spinning takes more time before a usable piece is finished.