Step 1: Marking and cutting the Gears
Also note the additional holes marked "#25". These are mounting holes for the connecting rods that join to the parallel arms. They need to be drilled with a #25 drill bit, and then tapped with a 10-24 tap to accept the shoulder bolts that act as pivots for the connecting arms.
Step 2: Cutting the Chassis Plates
Step 3: The feet and knob
The knob can be any shape, but I made it in a similar shape as the gears. It needs a center hole, 1/4" dia., and a 1/4" shaft collar joined to the knob with a tension pin (see photos).