Why do most showers have 1/2 BSP-P threads?

No, that's over-snipped.

I said "Exactly ***but...***"

The 'exactly' refered to the concept of sealing a BSP-P thread with a washer. ( like a tap. ) The 'but' tried to explain why I couldn't in this case. Taps have a male thread, not a female.

So not 'exactly' meant not **quite** exactly, IFYWIM.

Sorry if the meaning got lost along the way.

Actually, I partially retract my previous post :-)

I just looked at it again. The *external* surface is actually smooth, and would probably accept a washer.

Not that it matters, I'll lard it up with PTFE or fernox regardless.

Thanks for making me look again.

Not the outlets, which is generally where you find this fitment.

I agree that they sometimes have 'em on the inlets as well..once again the small width of this is an issue when fitting behind a plasterboard wall etc.

Beware then. I run mains pressure and ALL my 'plastic' heads have blown their O-rings..and been replaced with chromed metal..there are plenty of better quality sliding rails and shower heads available, and its just a matter of more PTFE tape to install em :-)

BTW I had a NASTY leak into the wall that turned out to be water running down the wall and into the hole where the pipe emerged through the tiles for the outlet..solved with generous amounts of silicon behind the decorative plate that covered the problem. .

Not all will hold pressure though. Air leaks are less noticable than water leaks and tend to get ignored, even though the energy required to compress the lost air can add up to a fair cost over a year.

I hired an electric thread cutting machine, which came complete with dies running from 0.5" BSP to 2" BSP. It involved very little effort at all.

I just have a box of odds that will make up almost any connection I want. Few need to be visible.

Colin Bignell

Sadly not.

If I owned an engineering company which had my name on it, I wouldn't be piddling about with DIY - I'd have one of my workers on the case :-)

( No point having a dog and barking yourself, as they say... )

Hi,

Why not phone Grohe and ask, they're a premium brand so must have a well staffed help line.

cheers, Pete.

Have you seen these?

Oh in that case you _do_ want something like PTFE and not some fibre or rubber washer which'll eventually disintegrate.

Test under full mains pressure (or better still with a plumber's test pump if you can lay hands on one, but they're over £100 to buy) _before_ you fix into the recesss in the wall.