I did a minor update on an apt bath. It's a 120 year old mansion conversion. The sink is an old bottle trap, I believe that's the correct term. The new sink is offset from the drain in the floor so I was going to just replace the strap with an s trap to allow alignment. A 1 1/4 drain pipe fits into the hub but a new 1 1/4 nut spins on the threads. It's slightly too large. The original nut is locked on the bottle trap tailpiece with a copper compression ring meaning I need to cut the pipe to remove it. I was hoping to save all original pieces until I got this back functioning. I've encountered this before and would like to stick pieces to fix it. What size is that fitting?