I found an interesting program on the internet called Sprocketeer, I needed a couple of #25 - 30 tooth sprockets for my welding turntable, I looked on the net and found this program, very simple and quick and outputs a dxf file and g code, the code had errors in it but the dxf loaded into Rhino, finished drawing it up and it worked perfectly! This one is 40 tooth, needed one for show and tell............