[frizzen]

Without knowing your plan for that axle, but thinking about gear mesh. It looks like you're thinking both bushing and bearings.

Would it work to thread half of the axle shaft so that you could run 2 thin plain nuts in a jam configuration on the right of that picture where the bearing is currently, to pull the mesh tight. Maybe do that on both sides for an easy adjustment of mesh and backlash.

Or a more difficult but much cleaner install could be milling a flat inside the pumpkin where the base of the crown gear sits, so that you can just shim the crown gears together. It'd be more annoying to set up, but your axle tubes could be thinner and it won't weaken the shaft like threading would.