Originally Posted by John E
My 1980 Peugeot PKN-10 is Swiss-threaded. Before investing lots of money in a new bottom bracket, borrow an English-threaded BB cup (readily available) and see whether it screws reasonably smoothly and easily into its respective side of the BB shell.
This makes sense, as Peugeot adopted standard threading sometime in 1980. I am absolutely positive that the bike in question is English-threaded...