Not my machine, but it appears if I want to do the side mount, it would indeed require the additional gear, hub, and spindle to make it work with the treadle - but if I wanted to not use the treadle, I could simply swap out the rear assembly to the side (maybe) and abandon the treadle. I think I will just spring for the parts, around $80 for the shaft, pinion, and hub. A second balance wheel would add more money and would be difficult to find but would also not be necessary. The picture I show looks like a 29-4 (or their about) at least that is the style of balance wheel they sported.