Originally Posted by
vintagerando
if you look at where the tube comes into the BB (photo 3), you can get a glimps of what I am referring to. If the BB openning is a clock, look at about 6 of 7 o'clock. You can see the metal I am referring to; its the butt end of the chainstay tube sticking out. On the drive train side, its more pronounced.
It looks like the builder already ran a tap through there, are there are threads right through the area you refer to. It might just need a little more chasing, or perhaps a different cup.