After reading here on CNC Zone I had an idea for combining my hobby of faceting (gem stone cutting/polishing) and CNC. This could be a very difficult machine to design and program, or not. I am wondering if this has been done before? :banana:
The way that a faceting machine works is different from a mill or a lalthe, as the stone is adhered to a dop stick and mounted into the index head which can be rotated and the angle of cut changed, the cutters are a 6" or 8" diameter laps of varying grits of diamond. Then after one end is cut the stone is transfered to another dop stick and the second end is cut and polished.
I was thinking that this might be a neat litttle machine because the range of motion would be very small (small steppers or servos) and the feed rates would be small as well.
I am open to ideas and suggestions for a good design, I would rather avoid mistakes if I can.
Dave

Well there are some computerized faceting machines...I've seen pics of some used for faceting diamonds....forget dop sticks...you'll need something more rigid and accurate. I'll see if I can dig up any additional information.

Thanks ViperTX,
The dop sticks are aluminum rods about 5" long and 5/16" dia. using 5 minute epoxy to adhere the stone. These are adequate for the stones that this machine will be cutting, everything except for diamonds because I would have to start over with a different machine and then try to find and purchase rough facet grade diamonds.
I have a Raytech Shaw machine that I have had since 1985, and it has only cut 200 stones, mostly sapphires and garnets, a few turmolines and some amethysts (quartz). Most of the cutting and polishing is done at low speeds 200 rpm and less, for example, Sapphires take a nice polish at around 5 rpm on a ceramic lap with 100,000 grit diamond.
So this will be a big modification of an existing machine.
I would really like to see those cnc faceting machines, that would make my designing so much easier.
Thanks
Dave