Mandrel n. : A bar of metal inserted in the work to shape it, or to hold it, as in a lathe, during the process of manufacture; an arbor.

Mandrel n. : The live spindle of a turning lathe; the revolving arbor of a circular saw. It is usually driven by a pulley.

Example:
How do you remove a nut on a Mandrel housing on a craftsman riding lawnmower?

Taxonomy
mandrel, lathe, expanding mandrel, Operation Mandrel, clamps, free encyclopedia, wire, circular saw blades, accompanying, metal, metal spinning, layers, Old shop, engine lathe, rotary tool, grinding wheel, pulley, arbor.

Defination from the web:
mandrel is a shaped bar of metal inserted in, or next to, an item to be machined or bent in a certain pattern. Exhaust pipes in automobiles are frequently bent using a mandrel during manufacture. ...