I could swear that I once threaded the (right-hand-thread) adjustable BB
cup into the (left-hand-threaded) right side of my Centurion Pro-Tour.
This was nearly 40 years ago; I was young and foolish.
When I figured out what I'd done, I pulled it out and could see no
damage (I know that should be impossible). Reassembled correctly and
rode the bike for many thousands of miles afterward, over 17 years.
If anyone told me the same story today, I would tell them they
misremembered, so maybe I am doing so, but the memory of the horror at
what I'd done - it was my first high-quality bike - is still quite fresh.
I've still got the frame. Maybe I should inspect those threads.
Mark J.