This is my circle cutting setup for the plasma cutter. The jig has a live center that tightens down onto the center of the workpiece. Under the workpiece is a small 2" turntable with a bearing. The plasma torch is clamped in place and size of circle is easily adjusted by unclamping and moving torch. This can cut up to a 32" circle. The torch is started and the workpiece is turned by hand (gloved hand - the piece gets hot!).