My house is 1920s, New England. its been upgraded and added onto a few times.

2nd floor toilet shut off was leaking.

I cut off the valve as I was unable to safely get a torch on it to un-solder it.

I shut off hot and cold water to the 2nd floor as the faucet and tub have mixing vales.

The supply ID is 1/2" so I got this 1/2 in. Nominal Compression Inlet x 3/8 in. O.D. Compression Outlet 1/4-Turn Angle Valve

To my horror, the OD of the pipe is 11/16 (maybe brass? older copper?)

As I understand, 1/2" copper is 5/8 OD so my part doesn't fit.


What part(s) do I need to button this back up?

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  • Not answer to your question but about the size, I wonder if newer pipes have thinner walls due material cost, better manufacturing etc – Ack Apr 11 '20 at 22:37
  • Photo of the pipe cleaned up might help. – Alaska Man Apr 11 '20 at 22:38
  • I'll try to get a photo in here, but really it's just a few inches of pipe coming out of the wall. 11/16 OD, 1/2 ID. Can't find adapters or valves to get there. – Zipper1365 Apr 11 '20 at 22:51
  • You can not get the nut and compression ferrule over the pipe ? Have you cleaned it by sanding it with emery cloth ? – Alaska Man Apr 11 '20 at 23:04
  • @AlaskaMan exactly. Pipe OD is too big. I haven't fully cleaned it up yet wit. but it's very clearly too big. I mean I could sand it down, but I would have to remove so much, I doubt I'd be able to keep it uniform enough to trust putting a fitting on. – Zipper1365 Apr 11 '20 at 23:10

Here is what I determined after some research

Some (many) people seemed to think that this was caused by water freezing in the pipe and expanding the tubing but others debunked that because it tends to split the pipe and there would be other evidence of the freezing. I also don't believe that it was a freeze cycle.

Pipe and tubing sizes were set in the early 1900's BUT apparently Westinghouse supplied an 11/16" pipe which was more commonly installed on the west coast but can also be found throughout the country. Some plumbing supply houses carried fittings through the 1980's until they were considered obsolete and unnecessary.

The problem was solved in a couple of ways:

  1. use a swage tool to sweg it out to receive a 1/2" pipe soldered on to it
  2. have couplers made out of copper stock on a lathe
  • 1
    Thanks for looking into that a bit for me! I suspect that this bathroom was redone in the late 80s or early 90s so that explains the source of the current (now removed) valve and the lack of availability of a direct replacement. I'm going to wait a bit to accept an answer in case there are other options out there, though. I'm hoping for a more or less off the shelf solution. – Zipper1365 Apr 12 '20 at 1:12
  • 1
    I accepted your answer since it addressed the question as it was posed. however. I've since discovered that there's a lot I don't know! turns out that this was/is standard 1/2 copper that had a sleeve over it. the valve and the sleeve were a packaged deal. that's why the walls appeared thicker and that's why noting fit it to do what I wanted. I have since been able to painstaking remove the sleeve and and attach a standard compression shut off to the stub – Zipper1365 Apr 30 '20 at 2:05
  • Thanks for the answer accepted and especially for checking back in to fill in the rest of the story, that will surely help others at some point. I'm glad that it worked out – Ack Apr 30 '20 at 3:26

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