Does the male threading of a 15mm compression fitting (like one side of a 15mm compression coupler) fit well into a 1/2" female thread?
I have confirmed that it screws in well, but, using PTFE tape, can it be secure and water tight?
If so, in picture at 'zSHARE - VG5V9782.JPG'
Thanks,
Antonio
apart from straight out viruses this is the most annoying spam that I have seen in a while.
That pushfit connector on the end of the isolation valve looks to be under a bit of strain ... I'd be tempted to support the plastic pipe.
Not really spam - he just has crap hosting. This is the pic he was trying to show you
No, it's a parallel 1/2" BSP male thread, screwed into a parallel female thread. You may get it to seal, but the joint won't tighten as it is screwed in. A screwed joint like that should be made with a taper thread. Buy a
1/2" compression to 1/2" male adaptor.
Or, rather, a 15mm comp to 1/2" male iron.
Bravo! Thank you for the helpful answer.
It brings up the key issue here. The difference between taper and parallel thread seems to explain it all.
However, following on your input, I have now researched the issue of BSP threads a bit further and, according to
If this is so, the initially proposed joint would be tapered 1/2" male into a parallel 1/2" female, which should be a fully functioning jointing thread.
Am I missing something?
P.D.: As you can see in the picture
P.D: Sorry for the z-share host> On 26 Oct, 21:09, asalcedo snipped-for-privacy@diybanter.com wrote:-
I'm afraid that you *are* missing something. A compression joint does
*not* seal on the threads - it seals by crimping an olive onto the pipe and by squeezing the edges of the olive between conical faces on the fitting and nut. The thread is *parallel*!When you screw a parallel-threaded male fitting into a parallel female, the seal is normally made between two faces by using a fibre washer or somesuch - and *not* on the threads. With the fittings in your photo, there isn't a face in sight!
OK, all of that is the official party line - the purist view, if you like. In reality, you could probably do what you want to do - and screw the valve directly into the tee. If you screw it in as far as it will go, *something* will stop it going any further. This may be the end of the valve bottoming in the tee, or it may be that you've run out of thread on the valve. Either way, there will be metal to metal contact which - assisted by copious amounts of liquid PTFE, will almost certainly provide an adequate seal.
Hello Roger, thank you again for the helpful answer, which I agree with fully and settles the issue.
One related question, when one screws a brass threaded male into a brass threaded female (like the brass adaptor into the brass tee in the picture), I assume that the male thread is tapered. Is this correct?
And a follow up question. Is PTFE tape (or similar) always required when screwing a tapered thread into a parallel one? Isn't (theoretically at least) the taper enough to provide a metal against metal functioning joint?
I mention this because I know that in compression joints there is no need to use jointing compound or PTFE tape, the deformation of the olive provides the seal.
Is it because the brass threads are too hard to have enough deformation to provide a good seal?
Could it be that by not having to permanently deform the thread, by using the PTFE tape, one can always undo the joint?
'Roger Mills[_2_ Wrote:
Don't forget that the thread is a spiral - not a ring - so water can work its way round the spiral between the two components. PTFE tape fills up the gaps, and prevents this from happening.
No. It's because of the spiral. An olive, on the other hand, provides a complete continuous metal to metal ring at each end, so there are no gaps for the water to get through.
Thank you again Roger for sharing your knowledge.
Ant> ;2523999']On 28/10/2010 11:50, asalcedo wrote:-
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.