The Axle drive is a Surplus Crossfeed drive from an Ikonics Scanner,
(circa 1985). Note the "FlyMass" #1 on the back of the stepper
motor. The FlyMass inertia eliminates bounce transmitted.
The worm drive #2 at the front is coupled with a vibration dampener as
well. This assembly is forced by the black screw (below the FlyMass)
against the perpendicular Aluminum Drive Platen #3 which has a Hard Rubber
Track (attached by Super Glue). The Net affect of all this is a gear
ratio of about 1600:1 with Zero Backlash.