A lot has happened! We found all the parts we needed at ACE Hardware. Koodos to ACE. We are making the casters for the wheelchair our of steel gas line pipe. We got these parts from the hardware store but actual users in the third world would commonly encounter these parts around a junkyard or abandoned building. We decided against the rebar because after feeling it, we decided it was too weak and too rough to be an axle. The casters we are now using work PERFECTLY in the holes we drilled. Will post pictures soon.