http://www.hackaday.com/2006/08/10/record-cutter/

Here’s a pretty rough project for cutting records out of acrylic. It uses a standard turntable for the base. The carving head is a chisel shaped needle attached to a small speaker. Speaker movement is translated into needle vibrations. The head is hand cranked across the surface of the record. The final addition to the system is a vacuum hose to remove the acrylic threads. I wish they would have spent more time taking pictures of this thing than making flash animations.