[Doug G]

I have to agree with Cory and others here. Perhaps we are missing the point - is it that you want to learn how to machine stuff like this?

Otherwise go get a bike hub and fab something similar to match your drive shaft. I remember we used to get those skyway wheelchair wheels and either used the spoke couplers that FIRST supplied or one year we made our own so we could use a keyed shaft. Much simpler than the route you're taking.