You could use pieces of 1" steel, cold rolled, or 4140 Chromoly from any metal supplier like Metal Supermarkets (just like all the Attex machines came with). Then you could get some steel tube to slide over the axles and you could simply have some #40 sprockets welded onto the tubes. Drill a hole for through the tube and the axle for a bold, and then do this for all the other axles. You can get the sprockets from Buffalo Bearings. (716) 874-1720.