Recently was rebuilding Paul's 250 and while reassembling I needed to lock the primary. Well, I'll usually do rebuilds at my house, but in this case I was doing it in the factory. Hunted around for a bit of aluminium to lock up the gears but all I had was a few bits of scrap 6061 T6. I can now tell you that this is not good. 6063 is much better, and a lot cheaper.

Just some useless info for y'all