compression fittings

Don't think so.

I think they are for connection to iron pipe or possibly to connect to tanks etc.

Someone will be along in a minute I'm sure...

A compression fitting has a internal taper for the olive. A male coupler not.

IME almost always yes.

No unfortunately, would be handy it it was.

A 15mm compression to 1/2 BSP male will have a flat on the threaded end to seal against a washer.

In a pinch where needing the above, I've used a 15mm compression coupler and sanded a flat on one side with medium/fine wet'n'dry paper.

cheers, Pete.

Sorry, I should have known that because 22mm and 3/4 inch fittings can be used together only with special olives, can't they.

I've got a few 15mm straight couplers so I was hoping to use them, rather than drive and buy something. The petrol would cost more than the part! I think in this case, I will get away with a straight couple.

A few years ago I bought some special olives - at a much greater price than standard olives - and found they were not special at all. So I took them back and used a special one I had in the meantime found down the back of the sofa (or similarly silly place). Company refused to accept there was a problem. Don't buy from Focus (I wouldn't normally but was the only place I could get to before shop closing on a Sunday afternoon)!

I think you will find that if you buy your olives from a genuine Italian grower that they are very special indeed.

But are they 22mm or 3/4" ? :-)

We'll be having none of that imperial stuff. We leave that to the Romans.

I'm surprised Focus stock something as exotic as 3/4 in olives!

If the fitting fits the screwed connection, then it should be OK. Use lots of PTFE Tape. Baz

But how do you write 3/4 in Roman?

Surely they must have used XXIImm? Or should that be XXIIMM?

(Yes, I know there's a flaw in there somewhere...)

Or maybe they didn't have any pipework smaller than one digitus and microbore heating really only became popular in the MCMLXs.

Owain

Yes - hypocausts use pipes a wee bit bigger...

I used a few of these in my 1950's house. It was cheaper to use a 3/4 olive to couple up to some old low pressure (from gravity tank) pipework than replace with new 22mm pipe.

P.

When using a 15mm to 1/2 inch couple, such as Screwfix 12341, should a washer be used in the imperial side? I must confess I have always used lots of PTFE but never used a washer. Have I been doing it wrong?

I realise my OP was about male-male couples rather than these but even then, the male gets connected to something.

Thanks, Stephen.