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Stepper Motors and Gearboxes
To suppress noise, the steppers were mounted on sheets of Sorbothane and attached to the drive shafts with neoprene couplers.
Nema23 steppers were used on both the polar and declination axes.  There is a trade-off between step increments and maximum slewing speed and the decision was to optimize for finer increments.  Therefore a 5:1 stepdown gearing was incorporated into the stepper housing design.
The drive and output shafts were 1/4" precision steel rods supported on bearings recessed into the 3/4" aluminum base for the gearbox.  For the declination axis gearbox, a steel flywheel was mounted on the drive shaft.  The polar axis gearbox used two flywheels, a large one on the drive shaft and a smaller one on the output shaft.