How to convert a 15mm tap tail to a 3/8" fitting

[Adam Mada]

Hi,
I am trying to fit a replacement tap to a mini-sink that's built in to the top of a toilet. The original tap isn't made any more by the manufacturers - the nearest equivalent is apparently this one: GoodHome Lazu 1 lever Mini Contemporary Basin Mono mixer Tap | DIY at B&Q - https://www.diy.com/departments/goodhome-lazu-1-lever-mini-contemporary-basin-mono-mixer-tap/5059340214207_BQ.prd

The problem is that the cold water tap needs to be fitted into a pipe that is apparently 3/8" wide, whereas the tap tail it comes with is expecting a 15mm pipe, according to a plumber that came to see the issue but didn't have the necessary part.

I can find plenty of converters that convert a 3/8" tap into a 15mm pipe (seems to be how you fit European taps to UK pipes?). But I think I need the opposite, to fit a 15mm tap into a 3/8" pipe (actually the output of an isolation valve).

I can't find one anywhere I've looked, and the staff at the couple of shops I've asked don't know where to get one either. Does anyone have any ideas?

I thought about getting new tap tails that end in a 3/8 fitting. But the tap is a mini one and the end of the tail that needs to go into the tap seems to be non-standard - smaller than a M12 fitting anyway, perhaps it's M8 if I was to guess ? But I can't find one of those either

(Weirdly the hot water input goes into a standard 15mm pipe so that one is fine - but the cold water pipe is smaller - the hot feed was added later as I understand it)

Thanks for any help!

 

[Basher]

If I've understood correctly, this sort of thing should screw onto the 3/8" isolation valve, and provide a 1/2" bsp thread for the tap?
The 3/8" female threaded section might be too deep for the washer to seal, but ptfe tape could fix that!!

search for:

1/2" BSP Male x 3/8" BSP Female Brass Adapter With Washer​

https://www.stevensonplumbing.co.uk/1-2-inch-x-3-8-inch-bsp-brass-adapter.html

 

[Deleted member 120897]

These any good?

 

[Basher]

These any good?

But I read the OP has a 3/8" cu pipe with a 3/8" isolator on the end of it, and a 1/2" tap flexi (which is what the tap spec. shows)

Or this sort of thing would do it:
Amazon product

 

[Deleted member 120897]

But I read the OP has a 3/8" cu pipe with a 3/8" isolator on the end of it, and a 1/2" tap flexi (which is what the tap spec. shows)

Or this sort of thing would do it:
Amazon product

I think either fitting may work, isolators could be changed. Without photos or being on site, sometimes I find it hard to visualise.

 

[Adam Mada]

Thanks to you all for your thoughts, much appreciated!
That's right, I've a 3/8" pipe with a 15mm flexi.

I did want to take a photo as it's definitely hard to visualise it from my description, but I couldn't really get an angle I felt would help! I feel like the link in the first reply would work so I'll give that a go. Thanks to you all again.