I used 1/4-20 carriage bolts, washers and Nylok nuts to attach the carrier to the chair. Unfortunately, Lil Bit, my other daughter, decided that they ...
This is my 11 year old, "Booger". She had a bout with SCFE, (https://secure.wikimedia.org/wikipedia/en/wiki/Slipped_capital_femoral_epiphysis) which landed her in a wheelchair for 3 months. These 3 months included Maker Faire NC, which we had been planning to attend for at least a couple months before this happened. Knowing we were still going to go, wheelchair be damned, we needed a way to carry the inevitable SWAG without piling it all on her lap or my back. Here is my solution. This is my first instructable, so be gentle... critical, but gentle!
Step 1: Convienience items
Since the wheelchair was rented I couldn't affix any more permanent modifications, plus a permanent attachment of the rear mount basket would have rendered the chair unable to fold. After sewing her some tush cushion and adding a way for her to tote her water bottle, it was time to figure out how to attach a milk crate to the back of the chair.