I had un-threading on my Concorde Italian BB. until I finally torqued it hard and used a little blue loc-tite. Since then no problem. I had the setup with two adjustable cups and never really cinched them in tight enough. Instead I would tighten the rings to the shell quite hard. As mentioned above, the reason for the two adjustable cups is to allow for chainline adjustment, which is going to be of use to me in converting it to fixed in the future. I would thread my right side adjustable cup in to where I wanted it to be relative to the centre of my cog set, and then snug the left side to the BB. I should have applied much more torque when doing this, and then tightened the right side again. When this is done, it still allows me to undo both sides to clean and grease the BB. shell without too much effort.

It is interesting though that it is still in use. As John E. states, it is a flaw, but not a fatal one. I wouldn't discount buying a great Italian bike for that reason, but would prefer it were otherwise.

Very interesting posts on this thread. Very informed members must be the reason.