Copper pipe is 17mm OD

[billman5000]

Ran into this while doing some DIY repairs on a house built in 1949, which was built with under-slab plumbing and under-slab runs to radiators. I found that some of the copper water supply pipe (not radiator) was too fat to accept normal 1/2" fittings. After going completely mentally blank from confusion, I checked it against a 17mm metric wrench, it's a very good fit as shown in the pic. My theory is the builder had some 17mm in stock and used it. Does this theory make sense?

Needless to say this a major pain! Thank you.

 

[Plumber69]

Is it possible it froze and expanded a bit. Did you check the pipe further back

 

[Sponsor]

 

[Plumber69]

It may have been that threaded copper they used back then

 

[Reach4]

Maybe swage up to solder into some 3/4 K copper pipe?
Maybe swage a 1/2 inch coupling up enough to get over that pipe?

Maybe solder into some " 5/8" copper pipe? Type L is 0.668 inch ID (16.967 mm) and adapt from there?

https://en.wikipedia.org/wiki/Copper_tubing

 

[hj]

"Threaded copper pipe"? Ridiculous, maybe IPS brass, but NEVER copper. If he had some 17 mm in stock, he would have needed a bunch of fittings for it, and WHY would he do that? He would have even greater problems finding "5/8 i.d. fittings".

 

[Jadnashua]

1/2" copper pipe is 5/8" OD...the ID varies based on the wall thickness, but the outside stays the same so you can use 'standard' fittings.

 

[FullySprinklered]

Maybe the cutter pushed up a ridge larger in diameter than the internal size of the fitting, preventing the pipe from seating in the fitting. You may need to dress that cut before you fit it. If it's K copper, it could be a little more difficult to work with, but I don't see any reason why standard size fittings would not work for you.

Y'all using the metric system up there in Indiana now?

 

[billman5000]

I can't explain it but appreciate the feedback. I have a 4' hunk of straight copper 17mm pipe in the garage. I emoried a section, it's copper. It's 17mm throughout the length. I have no idea how on earth one would connect it to anything. It's just weeeeeird. I'm gonna bite the bullet and hire a plumber to pex me up. I've had 2 pinhole leaks in copper supply - plus a soldered copper (h0t water) connection that came apart - in 12 years. Pipe is 70 years old now, I know it lasts almost forever. A real plumber can work > 10x faster than me and put an end to this nonsense.

 

[Dj2]

"...and put an end to this nonsense."

Not always, PEX has its share of chronic troubles.
Choose your plumber and materials carefully.

Like the old saying: "Escaping fire , falling into deep water".