Tapered or straight fitting

[mike42]

HI

I'm planning on fitting a hansgrohe ibox and it has what it describes as G3/4" and G1/2" female threads for connections. It doesn't state whether the female thread is tapered or not but I presume it isn't?

Does that mean I can use something tapered like this to connect my 22mm copper pipe with ? (and similar 15mm/1/2" for the outputs)
http://www.screwfix.com/p/conex-male-straight-connector-taper-302ta-22mm-x/72171 (with loctite 55 or similar)

Or could I use a non-tapered thread which seem to be a bit cheaper?

Thanks in advance if someone could quickly point me in the right direction here.

 

[Nige F]

HI

I presume it isn't?



Or could I use a non-tapered thread which seem to be a bit cheaper?

.

That`s the one

 

[Jackrae]

It actually DOES state the female thread form.

The "G" refers to "gas" and is parallel for both male or female (ISO 228)

The other designators relate to "pipe" thread (Rohr in German)
and they are :
R male taper
Rs male parallel
Rp female parallel
Rc female taper

"G" type threads are designed to seal via a washer, "pipe" threads are designed to seal by interference of the thread. Or to put it another way, "pipe" taper fittings are not designed to fit into "G" parallel fittings and vice versa.

Having said that, I looked at their installation video and it appears to show taper fittings being screwed into the assembly. All very confusing !!!

 

[ALCPlumbing]

Just buy a 3/4" female iron to 22mm compression.

Good choice by the way. The ibox's are good quality and much nicer and slightly easier to install that a standard concealed valve.

 

[ALCPlumbing]

Sorry you need male irons for the ibox.

 

[Jackrae]

Steel fittings might not be the best choice

 

[mike42]

Thanks for all the replies. So the female end G3/4 is definitely parallel (and now its in my hand it certainty looks it!)

BUT there are no washers supplied so is it definitely not designed for a male tapered thread ? Maybe it could be used with either? If parallel male is the way to go then then should it be fibre or rubber washers?

In the scheme of things there isn't much difference in price between parallel and straight (esp if I end up having to buy washers if I don't have them already)

 

[doitall]

If you use a taper thread in a parallel thread only 2-3 threads will actually be mating unless you stretch the female thread and risk splitting the fitting.

 

[mike42]

That makes sense but I've just realised that this ibox comes with a set of 3/4 to 1/2 reducers which are themselves parallel. So, that confirmed to me that (and I know I shouldn't need confirmation!) that you guys were right and that I just need to supply my own fibre washers.

However, if I was to use the reducers, I'd end up with a 1/2" female straight thread with stop at the end to screw against !!! That says to me the joint must be with the threads - so maybe parallel on parallel with a lot of pfte/loctite-55 etc.

Basically I'm pretty confused and I really want to get it right since its going to be behind tiles etc. I also saw http://en.wikipedia.org/wiki/British_Standard_Pipe which seems to suggest that tapered into parallel is normal (even though its only using 2 or 3 threads as you say).

Thanks a lot for your thoughts so far by the way.

 

[doitall]

I always found a packet with the washers in the box.

Perhaps you should check with the supplier.

 

[mike42]

I'll do that but you can't fit a washer when there is no "stop" to fix it to?

 

[doitall]

Isn't the stop in the ibox female end.

 

[mike42]

Yes, but if you fit their reducer then you have a 1/2 inch female thread with no stop at the end. That's why I'm confused.

 

[Richardthe3rd]

Just a wee point here for the hard of thinking; some parallel thread fittings have no small shoulder & some do. This can be confusing as most tapered thread male fittings have no shoulder. Happy to help!!

As my learned friend DIA has rightly pointed out; don't use a tapered brass male compression fittings on a parallel female thread, it'll leak like a 1 month pup.

 

[jeff the gasman]

For me it would be parallel thread with loctite string. No leaks no washers to compress, deteriorate.