Re: pic: FRC 1771 Swerve Module
 

Right behind that snapring you see is a 1/2" hex followed by a step of 1/2" round for a bearings then it steps down to 3/8" hex for the wheel then at the very end it turns into 3/8" round for another bearing and snapring.

Re: pic: FRC 1771 Swerve Module
 

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.

Re: pic: FRC 1771 Swerve Module
 

That method would definitely work although bigger bearings are more expensive and its heavier but if thats how you have to do it then by all means use that method. It will definitely work and would be less labor intensive.