[Nemo]

Our FTC teams have used drilled out axle hubs with the McMaster D-shaft in both 1/4" and 3/8". We still had some problems with wheels spinning free of the axles, but at least the axles didn't twist into spiral shapes. We used bronze bearings in aluminum that had been drilled out to fit the bearings. It adds time and complexity, but we preferred that over twisted and bent axles.

Now that the build rules have opened up even more, we might make liberal use of hex axles.