Ok, this is a strange one.
I recently built up a new steel frame, with a Shimano UN-54 square taper BB and Sugino XD-600 cranks. The frame manufacturer recommended a 107mm BB, but i went with a 110mm at the recommendation of some other people who have this frame, because of the tight clearance.
All parts and the frame were brand new.
While installing the plastic removable sleeve of the BB, i used the wrong torque specification and broke the plastic, so i took it down to the LBS to see if they had any replacement sleeves. The mechanic there tried a whole bunch of sleeves until he found one that fit - it was an aluminum one too, which i figured was a good thing. He reinstalled the BB and the sleeve, cranked everything down, and i figured i was good to go. It looked like he was REALLY cranking it down too. I did ask him if the threads or BB shell needed chasing/facing, but he looked at me as if i had suggested he sacrifice a chicken over my bike, and shook his head. I only mention this in case it has relevance later on..
I then took the bike home and installed the cranks myself, using a torque wrench and being conservative with the torque (using the lower end of the recommended torque). There was a good 2mm of clearance between the granny ring and the chainstay - tight, but OK.
I rode about 25 miles, re-tightened the cranks (they had loosened just a little, as is normal, i think), and then didn't have time to ride until today, when i went on a longer ride. About 30 minutes in, i noticed that the cranks were wobbling - closer inspection revealed that the BB was totally loose. I made it back to the car, by which time, the cranks were wobbling at least 6-7mm laterally (at the ends of the crankarms) because of the loose BB.
I got the bike home, took the cranks off, removed the BB, cleaned it off, scraped some paint off the drive side shell face with an XActo knife (the paint was cracking, presumably from the pressure of the BB's flange), and reinstalled the BB using Park Tool's recommended torques, about 400in/lbs on the fixed (drive) side and 360in/lbs on the sleeve side.
Seemed fine, so i tried reinstalling the cranks.
And here's the second weird thing. I installed the drive side crank again, to the same torque spec, and it went on so far that the granny ring got stuck against the chainstay, and actually gouged the paint pretty well before i realized what was happening.
So my question is... what on earth?
First of all, how did the BB practically fall out so quickly, and secondly, what happened to my chainline?
Really strange, especially considering i'm using a BB thats 3mm longer than recommended and the parts are all new and 'normal' (ie. no wacky combinations AFAIK). The only possibly non-matching thing is the replacement sleeve, but i don't see how that would have an effect on the chainline like that.