... you put the tool to the BB shell.


Initial cutting. Whenever you remove paint & metal in only one area or on only one side, you know the face isn't flat.



I don't really understand why, but it often takes a WHILE until the tool really begins to cut. And once it did, it cut really well. Took a fair amount of milling to get the face flat.





Ahhhh, so much better! As long as you have at LEAST a strip of bare metal, there's no need to go any further. Sure, I COULD have kept milling until the face was FULLY flat and all the paint was gone, but that means you're having to cut a LOT more material for zero improvement. As long as your cup is bottoming out on steel, there's no need for the ALL of the wall thickness to be perfectly flat. The other side was in just as much need for facing. This BB wasn't faced as it should have been.

Now, the BB shows no sign of wear, despite it being almost 50 years old (AFAIK). But the bike apparently hardly got ridden, so premature bearing failure was probably still in the cards for this OEM BB if I hadn't faced the shell.

Glad to have been able to get back on this bike project today.

PS Sorry the pics are so huge. I resized them to 35%, but they're still too big. Next time, I'll crop too.