Hey all.
My Home was built in 51'. I just installed a new drain,tailpipe assy' because it was cracked. While doing this I noticed that the PVC pipe attaching the pipe stubbed out of the wall was leaking so i changed that as well. The stub is 1 1/2, or so I thought? None of the large pipe nuts that came with my new P-Trap assy would fit (I went ABS).
My question is, did they use a different thread in the old days? Was the plumber that sold me the ABS rig wrong and you can't mix ABS with galvanized pipe from the 50's? Or is there something else?
Any help would be appreciated, Thanks.

The thread is the same, but oxidation has made the pipe threading swell. Attempting to thread plastic into an old cast fitting isn't impossible, but without a tap(or die) to cut/clean the threads, you don't have much of a chance. If you were to use a piece of 1.5 inch galvanized, it might go. Once it gets about one full turn inside the threading, you can generally get it all the way in. I don't know what you have inside the wall, it could be lead and brass, galvanized and cast, or a combination therein. If you can post a picture, it would be helpful so that everyone can see the pipe, configuration, etc. and can advise you better.