Indexing is the process of turning a work piece a certain part of a circle between milling operations. A simple indexing operation is milling the flats on the head of a bolt. A more complex indexing operation is cutting gear teeth.
On mini mills, most indexing is done using a rotary table. The addition of dividing plates makes indexing easier. When working with relatively long work pieces, a tailstock can be used to support the end of the work piece. In many cases, a lathe chuck is mounted on the rotary table to hold the work piece.
Indexing spacers and indexing spin jigs are also used for simple indexing.