The nema 23s might be enough if you are using the acme threads to drive. Ball screws have a much faster pitch. I went with the reduction so i can add ball screws later if i feel the need.

I run the nema 34 80v dc servos with low backlash 5:1 gear reduction on the x & y. For the z i went with a slightly larger 1100 oz-in 80v dc servo with a 10:1 reduction due to the large gearhead and 220v motor it has to lift.

The servos will spin up to 3000 rpm so even with this reduction the inches per min are good. As for the different gear ratios, the two on the table are matched. Servo tuning makes the larger servo run faster to match the inches per min called for by Mach.

Most breakout boards have room for up to six axis. So adding another drive is simply plugging it in and wiring it up. I went with a 4th axis setup as you mentioned "fourth axis indexing/dividing heads complete with tailstock, 3-jaw chuck and motor drive." It is a nema23 drive on that.


Andy