Hi Rudy,


You might be thinking of the A axis on a CNC milling machine,
which CAD jewelers use for cutting rings and two sided parts.

The rotary "A" axis on my milling machine has a 4-jaw chuck that holds the material.
It's set up in the CAM software so that that when the front side is done,
the software automatically turns the rotary 180 degrees and then the the art work on the back is carved.

-Jesse