Well firstly look at the torque curves for the stepper to determine the RPM, you'll see that the torque of the stepper decreases rapidly as the RPM increases.....so, go with a stepper in the 400 oz-in torque, remember ACME screws are only 40 to 50 % efficient....so, you'll lose half of your torque just turning the screw, directly couple your steppers, use a 3/4 inch ACME screw....why....are you turning your own ends of the ACME screw? |