Hi Al,
I had the same problem when I installed new bushings into my Ross box. I ended up buying a brake wheel cylinder hone, and after installing the bushings, I used my drill and the hone tool to open up the I.D. a little bit at a time until the shaft fit inside. It was rather tedious as I'd hone a bit, clean it up, oil it, then try to fit the shaft. I did it quite a few times so that I wouldn't overdo it and have a loose fit. It worked out nicely.
I did polish the shaft a bit with some 1500 grit paper too, by hand....just to debur it and clean it up.
Good luck!
dAve