[ollopa]

OK, as I understand it NEMA 23 is a size of motor rather than a particular type. I believe it corresponds to the mounting face.

At any rate, you need a "driver" circuit (not software but hardware!) to translate the step/dir signal from the compuer into motion at the stepper motor. The cheap and common drivers (like the PIKER) are for 6-wire unipolar stepper motors.

So pick a motor/driver combination and keep them consistent--voltage, uni/bipolar, etc. If you're building by the plans or trying to keep costs down, you probably want 6-wire unipolar stepper motors about 5 volts, 50-100oz-in.

Also, the "oz" is not the weight of the motor but the holding torque in ounce-inches. In metric this is gram-centimeters (g-cm).

Hobbycnc has some nice ones that are 6v, 80oz: www . hobbycnc . com/steppers/steppers.htm

They won't make quite as much torque if you drive them with a 5v supply but they'll still run. You could also drive them with 12v and use a current-limiting resistor--they'd spin very fast but you might need to use an uncommonly large resistor. Perhaps someone with more experience doing LR current limiting will chime in here...