What size spanner for imperial/octagonal compression joint?

[Lusi83]

I have some old - I am assuming imperial- compression fittings in my house. Recent one was an octagonal nut but think previous one I had a problem with was hexagonal.
The nuts on the '15mm' -assuming 1/2" - compression joints are a wee bit too big for my 15mm compression spanner. Normally I would use an adjustable wrench/stilson but two have been in tight spaces which made those impossible to use.
The last one -an elbow - I had to cut the pipe off on either side where I could get to it and replace that section.
So does anyone know what spanner size I should buy that will fit? Hopefully one that will fit hexagonal and octagonal nuts...if that's possible
Not sure how many of the old fittings I have left or if any will be tricky to get to but would like to get one 'just in case' to save me future frustration. Wish I had got one last time I had a problem...
Would measure the one I have just taken off but as it is octagonal not sure ... I could get 2 sizes if necessary.

 

[RandomGrinch]

Might it be easier to just stop using the old fittings and use some push-fit, or soldered fittings instead?

 

[kidgreen61]

Adjustable spanner?

 

[CBW]

The nuts on the '15mm' -assuming 1/2" - compression joints are a wee bit too big for my 15mm compression spanner.

Metric are mm, not inches (imperial) and is for the size of pipe, not the nut size or not the spanner size to tighten up or undo the nuts. An adjustable spanner/pump pliers et al is what you need, or sometimes a 24mm open ended spanner.

 

[Lusi83]

Might it be easier to just stop using the old fittings and use some push-fit, or soldered fittings instead?

I do generally replace them - the problem I have is when I am attaching new pipework to existing piping and I can't get the old fittings off to that...

Adjustable spanner?

Isn't that the same as an adjustable wrench? Which is what I have used - but they are quite bulky and in this case I couldn't get it to turn enough to catch on the next 'face' of the nut - if that makes sense. (I should say the pipes were put in by a previous owner who I call 'Mr. Bodge-it' for good reason. I suspect he may have assembled the pipework before attaching it 'neatly' - 1cm up from the plasterboard of downstairs ceiling with lots of pipe brackets along a joist that runs under the floor/shower cubicle etc so I can't get to the brackets to move it away...)

sometimes a 24mm open ended spanner.

Sorry - I meant a compression fitting that was for 1/2" pipe rather than 15mm pipe. I know you can use 15mm fittings on 1/2" pipe but I don't think you can do it the other way round (although I am getting confused now!) Actually thinking about it the nut should be slightly smaller - (1/2" is equal to 12.52mm...I think) I guess for some reason the nuts on the compression fittings he used are extra large ones ... so I guess there isn't (or at least wasn't) a standard size for compression fittings?
I'll get a 25mm and a 26mm spanner to try ... like I said I have one of those double ended compression spanners (for 15mm and 22mm pipes) - I'm guessing the one for 15mm pipes will be 24mm and that isn't big enough.
(knowing my luck I need a 27mm one!)
Thanks for your help.

 

[CBW]

Can you post a photo of the fitting?

 

[Lusi83]

Sorry - I didn't see your reply until just now! The ones I took off have now been thrown away and rest are covered up again so I can't really do a photo now.
I came back to post for anyone else that I did get a 25cm and a 26cm spanner and the 25cm spanner is the right size (worked on the hexagonal and octagonal nuts). 26cm is too big.
Now that I have one it is almost guaranteed I will never have that problem again!

Thanks again for everyone's help

 

[CBW]

26cm is too big.

So is 25cm! Think you mean mm.

 

[Lusi83]

Whoops - yes 25mm is the right size!