Originally Posted by
JimboMartin
In partial answer to my own question about videos,
here is one with a very nice detail. See what he does between 1:00 and 1:15. Would have never occurred to me that two concentric tubes might not be parallel.
Looks to me as though he is making sure the BB shell is square to the tube. There's not really a lot of contact area between the tube and shell, so the looser the fit, the more crooked the shell could be. I built a few frames when I was a kid and built a jig in the basement. I held the tubes in the fixture, and then had round "dowels" that fit inside the BB shell to hold it perpendicular to the tubes. But the shell was not clamped, so there was room for it to float a bit during heating & cooling.
As for the first 10 frames being disasters, I hope that's a bit pessimistic. I never even built 10, & I am still riding the 2nd frame I built. I should have done a few more braze-ons, and the seat lug could be a bit cleaner, but no real disasters.