1 3/8ths inch (1.375) sink drain pipe

[Boburk]

Remodeling a structure built in 1960.

The drain (waste pipe) for the bathroom sink has a 1 3/8ths (1.375) inch OD and is made of brass or copper. Currently this pipe is flush with the drywall and I need to adapt it to fit a vanity/sink when I pick one out. I have been to both of the local big box stores asking for suggestions on how to adapt this to modern sink waste drain pipes with no luck. From my discussion with them, 1.25 is normal for bathroom vanities...so this is what I am trying to adapt it to.

Closest suggestion I got was someone saying to use a 1.25 to 1.25 inch rubber union...but measuring the uncompressed union showed it had an ID over 1.5 inches. A softer rubber (thinner?) one that actually measured 1.25 ID might work (if I can stretch it over the 1.375 inch pipe and put a clamp on it), but I have been unable to find such a critter. I figured I could roll it onto itself on a metal 1.25 inch pipe, slide that into the 1.375 and unroll it over the union between the two pipes and put two clamps on it.

Any input would be appreciated.

Thanks,
Sean

 

[MKS]

Not a pro.
You need a trap adapter on the end of the pipe that is inconveniently cut flush with the wall.
Opening the wall and replacing or extending the drain pipe into the room/cabinet and adding a trap adapter is probably the solution.
https://www.plumbingsupply.com/trap-adapters.html
A non brick and mortar plumbing store could provide support and appropriate fittings like these.

http://www.fernco.com/plumbing/shielded-couplings/proflex-couplings

They are available in many sizes to connect various types of pipes together.