thread size

Having trouble fixing a leak so need to confirm a thread size. a bottom entry float valve

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it 1/2 " bsp or metric?

Thanks.

Arthur

Reply to
51
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> Is it 1/2 " bsp or metric?

Well whatever thread it is it's pressure rating is 'interesting' - to quote "withstands pressures from 1.5 to PSI " - maybe 'PSI' is some strange newfangled utterly horrendous pressure !

AWEM

Reply to
Andrew Mawson

Sounds a bit kinky...

:-)

Reply to
Frank Erskine

BSP is an ISO standard thread, which makes it officially a metric thread. Most domestic tank and cistern fittings use 3/4" BSP, which is just over 1" OD. If the one on that valve is 1/2", the thread OD would be about 3/4".

Colin Bignell

Reply to
nightjar

"nightjar .uk.com>"

Thanks, Colin.

Reply to
51

Are you *really* sure of that?

Reply to
Matt

The message from Matt contains these words:

My now rather old reference states:

"British Standard pipe threads are recognised by ISO and are maintained in the inch system with fractional designations for pipe joints."

The dimensions in the tables are metric apart from TPI.

Reply to
Roger

Under EU legislation, all threads we use must be metric, even if they have to produce metric versions of threads that started out as imperial to achieve that.

The relevant standards are ISO 228 and BS EN 10226

Colin Bignell

Reply to
nightjar

Currently being nowhere near my usually easily accessible Zeus tables/Kempes/Machinery's Handbook i'll take your word for it!

Bloody strange state of affairs when it has to be dimensioned in metric though. Probably to suit the Germans/French who couldn't devise a sensible thread if their life depended on it. PG threads used (or not) for conduit/industrial switchgear are one of the most obscure.

They have a Metric OD (but ridiculously referenced so that PG 13.5 is actually just over 20mm, not exactly 20mm mind as that would be far too sensible - (20.4mm to be exact), 18tpi pitch which equals 1.41mm yes 1.41mm, not 1.5mm as that might remotely make some sense and an 80 degree thread angle so they can't be cut using common off the shelf tooling.

Why on earth would any sane person bother with PG crap when 20mm or larger conduit holes can be punched for 1/10 Euro cent and use standard conduit fittings that have been around for three decades?

Reply to
Matt

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