Mike,

Jazz and I designed a single ball screw machine and when it all came down to it the cost for the pulleys and belts where actually more then going the twin screw route. Now I have to get a second parallel port card to allow me to bring the 4th axis on line and set up a second BOB and driver set up. But outside of materials this is not really a problem when using Mach3. Good luck and hope all things go well.

Michael