Used a few of those mike
infact i lost one of the bearing washers on my rear derailleur jokey wheels about 3 months ago and its still bodged
worst one i had to do to get home was bend the forks on one of my racing bikes in the early 90's , while out training in the ice xmas morning (yes i was obsessed)
i came off and bent the forks, i used a gutter to bend them back, plus bent the ali derailleur hanger so had to use a small adjustable spanner to bend it back, the bike was a vitus 979 , worked fine after but i replaced the forks later on ,
paul