Re: new prototipe project
Is this a very large machine? For the X axis you may need a larger motor depending on how much mass you are moving. For the Y and Z axis NEMA 34 steppers should be OK.
I also am going to add CNC to my 618 surface grinder, and will be using NEMA 34 steppers, direct drive on all axis. But I think my machine is much smaller than yours.
You can run the X axis from G code with Mach3. I think you will need to hand write the G code, but it might be possible to use a facing routine generated from a CAM program. I would need to experiment with it a bit to figure out what works the best.
Jim Dawson
Sandy, Oregon, USA