Originally Posted by
SkyDog75
I have one bike with a Tange bottom bracket like that one and a 15" crescent wrench worked well enough on the fixed cup.
...not that everyone has a big-*** crescent wrench laying around, but if he does, it should do the trick.
My recommendation to clamp the flats in a large bench vise was along the same lines. Not everyone has access to one but if you do it works.
However as John notes, removing the fixed cup is necessary only if you are completely replacing the bottom bracket because it is damaged or you are going to install a different type.