[JesseK]

The other option you have, if you don't trust your machining skills, is a brass sleeve bearing from mcmaster (or such) that you press into the KOP bearings. We used 1/2" OD 3/8" ID bearings, but it was tough to press them into the KOP wheel bearings without breaking the bearings. Once we finally did it, it worked like a charm for 2 full competitions.

Could have told you this earlier, but wanted to let you think on it a bit. Plus, there's always 2 ways around a problem.