M12 “short” tail connection

[23vc]

Hi
Need to connect 15mm pipe to m12 monobloc female threaded socket, on one of those silly floor standing monobloc bath taps. The only rigid tails I can find, taper up from some unknown bore (not 12mm, a bit bigger so presumably 13mm) before reaching 15mm too far down the tail. I’ve got very little scope to change existing pipe work if I can help it. Don’t want to use flexi hose as (a) it’s inaccessible and (b) because the distance is so short, it’d have a nasty tight bend to take up the slack.
Anyone reckon I’ve got any chance of doing this? Thought about trying to solder/sweat the narrower tail section inside of a 15mm tube, but I’m not sure if that’s a goer.
Pic attached shows arrow pointing to where I need it to become 15mm.

 

[lostinthelight]

Have you access to silver solder and flux..that would give a perminant joint

 

[MeldrewsMate]

Have you considered chopping the photographed adapter close to the M12 end, then soldering on a 12mm - 15mm reducing coupling?
On the other hand, have you considered how you will maintain such an inaccessible bath tap - nothing lasts forever?

 

[23vc]

Have you access to silver solder and flux..that would give a perminant joint

happy to solder yes but which part/where? Issue is, the reduced bore copper section is not 12mm so doesn’t fit in a 12mm coupler

 

[23vc]

Have you considered chopping the photographed adapter close to the M12 end, then soldering on a 12mm - 15mm reducing coupling?
On the other hand, have you considered how you will maintain such an inaccessible bath tap - nothing lasts forever?

yep, did that, then found it’s not a 12mm bore, so doesn’t fit in my 12-15mm compression reducer. Accessibility is ok, I can get to it in future, I just can’t chop back the existing fixed pipe work any further, if that makes sense

 

[lostinthelight]

Hi
Need to connect 15mm pipe to m12 monobloc female threaded socket, on one of those silly floor standing monobloc bath taps. Thought about trying to solder/sweat the narrower tail section inside of a 15mm tube, but I’m not sure if that’s a goer.
Pic attached shows arrow pointing to where I need it to become 15mm.

If you silver solder the tail inside a short length of 15mm you can soft solder an end feed or use compression fitting to join into main pipework, silver solder has much higher melting point so wont fall apart

 

[MeldrewsMate]

yep, did that, then found it’s not a 12mm bore, so doesn’t fit in my 12-15mm compression reducer

Then what outside diameter is it, sir? UK 15mm pipe is 15mm o.d, with a 0.7mm wall thickness. Fittings are made to accept 10, 12, 15mm o.d pipes.
Continental (lets quote French) are 10, 12, 14, 16mm o.d, but with a 1mm wall thickness, so they will solder into the next size up.
Additionally you could try using 3/8" air conditioning pipe, imperial sizes, etc.
Finally heating the pipe and tapping a pipe expanding tapered shaft inside it may achieve the required outcome.

 

[23vc]

Then what outside diameter is it, sir? UK 15mm pipe is 15mm o.d, with a 0.7mm wall thickness. Fittings are made to accept 10, 12, 15mm o.d pipes.
Continental (lets quote French) are 10, 12, 14, 16mm o.d, but with a 1mm wall thickness, so they will solder into the next size up.
Additionally you could try using 3/8" air conditioning pipe, imperial sizes, etc.
Finally heating the pipe and tapping a pipe expanding tapered shaft inside it may achieve the required outcome.

It appears to be about 12.5mm. I know this sounds like I’ve measured it wrong and it’s 12mm, but it deffo isn’t, and it’s also deffo smaller than 13mm. I might try and file it a bit to see if i can get the 12mm nut and olive over it, but it won’t oblige as it is.

 

[23vc]

If you silver solder the tail inside a short length of 15mm you can soft solder an end feed or use compression fitting to join into main pipework, silver solder has much higher melting point so wont fall apart

cheers. Not sure if I trust myself to do a type of joint that I’ve not done before, and sleep at night! But Good to know it’s an option

 

[JimCrow]

yep, did that, then found it’s not a 12mm bore, so doesn’t fit in my 12-15mm compression reducer. Accessibility is ok, I can get to it in future, I just can’t chop back the existing fixed pipe work any further, if that makes sense

Forget the nut and olive, chamfer the pipe end and clean it and the inside of the reducer and tap it on and sweat it, if it still wont go
on ream out the inside of the fitting with a drill bit.

 

[23vc]

Forget the nut and olive, chamfer the pipe end and clean it and the inside of the reducer and tap it on and sweat it, if it still wont go
on ream out the inside of the fitting with a drill bit.

cheers. So solder the pipe into the compression socket (once I’ve got it in somehow) and do away with the olive and nut?

 

[JimCrow]

cheers. So solder the pipe into the compression socket (once I’ve got it in somehow) and do away with the olive and nut?