[Ice Berg]

Well, my team doesn't have the machining capabilities to make a shaft like that, however, I thought about it and I think I've found a simpler solution in terms of machining. Instead of lathing anything on the hex shaft, we would use a 3/8" shaft all the way through, and where we needed bearings (on either side of the module) we would make a sort of bushing whose inside would be broached to a 3/8" hex, and whose outside would be a 5/8" dia. circle. This way we could put a hex shaft through the center and use a 5/8" bearing around the outside, and snap-rings to hold it all in place.