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very odd sized pipe

Postby chris_on_tour2002 » Thu Jan 08, 2009 8:10 pm


i want to connect up two ends of a copper cold water feed pipe that i recently cut when installing a new outside toilet.

interestingly i can find no fittings that will work.

looks like some kind of microbore but it's not - took a piece to the local microbore merchants.

i thought at first it was 12mm, so i bought a 12mm-15mm reducer - no joy. the pipe is a fraction too big to get the olive on but way too small for a 15mm olive.

i think it might be 13mm??? any ideas what it could be? have tried about 5 different plumbers merchants but no joy. the house is 1920's but i don't think the pipework is quite that old (otherwise would be lead?) but could date from just about anytime between now and then.
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Postby plumbbob » Fri Jan 09, 2009 12:07 am

If it's the one I am thinking of, it's been ages since I have seen this and I can't remember what it's called but it was the first copper pipe to be installed. You can identify it as the joints are threaded and the pipe wall is really thick. Also, the fittings have a rib around the lip just as modern iron fittings do.

As for size, well, it's probably 3/8" or 1/2". I know normal 1/"2 is larger than 15mm but this is a different kettle of fish altogether. If you can undo one of the joints, you may find a modern fitting to screw in, but then again it may be a wonky thread. I doubt if it is BSP.

Just a point, have you tried fitting 15mm cut with a hacksaw over the pipe?
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Postby Steve the gas » Fri Jan 09, 2009 6:21 am

Hi Chris,

After chasing about a lot, I would now repipe it in 15mm 8)
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Postby AdamsHeating » Fri Jan 09, 2009 8:36 am

hi mate,

a quick google search suggest that they are still making pipe in the following imperial sizes... (inches of course)


check out the website, it is:

World Wide Web - DOT - ftipv - DOT - com

Maybe that helps?

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Postby chris_on_tour2002 » Fri Jan 09, 2009 10:33 am

thanks for the responses. having now measured the pipe in imperial it appears to be closer to 7/16". very odd.

replacing with 15mm is alas not really an option as there is a decent run under concrete, job doesn't warrant digging it all up so i will still have the problem of marrying up with a tail. and due to its location surface mounting is not an option.

i have even taken the old compression fitting off and shopped around. problem is that the fitting is not the issue, 12mm will fit in there no problem. it's the olive. and obviously there are no endfeeds that will fit.

oh well, looks like i may have to dig out the floor after all...
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Postby htg engineer » Fri Jan 09, 2009 2:40 pm

Would it be easier to re-pipe in 15mm ? this would be the easiest solution - and will save any problems with future plumbing work.

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Postby swidders » Sat Jan 10, 2009 11:41 pm

One solution may be to flare the pipe and use a manipulative joint.

If you Google "" andgo to the literature section and then instalation tips, jointing compression.

and if you search ebay for thefollowing: 10 pce Metric Flare Flaring Tool Kit - Brake Fuel Pipe
for the sort of thing I'm talking about.

Bit more work, but the again, less that digging up the floor!!
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Postby TheDoctor5 » Thu Jan 29, 2009 1:28 pm

If you type the key words of your question into our search box to the left of the site you may find the answer is already posted or is in the DIY projects section of the website. Every post goes through a monitoring process and using the search box may speed up your answer.
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