Quote:
Originally Posted by Kevin Ray
The first thing to address in adapting the pneumatic wheelchair wheels to this year's game is the bore size. We insist on 1/2 inch shafting (always captivated on both sides of the wheel) for all drive systems--especially this years game!!! If the bore is smaller than 1/2 inch you'll have to modify it; easy enough to do. First purchase 1/2 hubs (with the bore (hex, round-keyed) matching the output shaft of your drive gearbox from AndyMark or such. Second, align the hub over the wheel and insert a shaft matching the size of the wheel's bore through the hub and into the wheel. Insert a spacer around the shaft to fill the space in the hub. This ensures that the hub remains centered. Mark, drill through the hub's holes into the wheel and bolt the hub to the wheel. Now, unbolt the hub and remove the smaller bearing in the wheel and replace the hub. It is STRONGLY advised that a second similar hub be placed on the opposite side of the wheel to captivate the wheel since the shaft is now "free floating" in the bore hole created by removing the original bearings. This can all be accomplished with nothing more than a drill press and wrenches. Please note, the center of the hub (the top hat part) should be inserted into the newly created hole in the wheel's center as close to a press fit as possible.
P/M me with questions on how to easily drill out any size hole to ensure a tight fit for the hub (using only a drill press).
...hope this helps.
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That is really great! When I was trying to figure out how to do this, properly centering the hub over the wheel was the real sticking point. As long as you can find a spacer to go inside the hub that would be tangent to the hex hub bore and also fit snugly on whatever shaft you inserted then I imagine you are fine. I think that's what we were missing but a quick order to McMaster should fix that.
I think this really helps to answer the OPs question as well.