Metric pipe sizes???

[spider007]

Our company Mostly does plastic injection molds for US, which means that they are all standard (imperial) sizes, and we never had a chance to do any metric stuff.

This is a first time that im designing a mould in Metric. So my question is. Is there such thing as metric water lines (pipe thread sizes) (forgive me for a retarded question).

I remember once (when i was on the shop floor) pluging water lines with STRAIGHT pipeplugs, and i remember job being metric. But averybody up here is telling me there is no metric pipe sizes.

 

[MikeHalloran]

Everbody is correct, sort of.

ISO adopted BSP(tapered) and BSPP(parallel) pipe threads.

Study your Swagelok catalog; they have adapters for most possible situations.



Mike Halloran
Pembroke Pines, FL, USA

 

[patprimmer]

As I understand it, The USA uses NTP threads while the rest of the world uses BSP threads. They are both imperial, but have slightly different pitches.

On most sizes I have used, they start, but bind after 2 or 3 turns and leak. In an emergency you can generally make them work with plenty of thread tape and thread sealing compound, but it is not pretty.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Pud]

If you are design a mould to be used in Europe, all the waterline fittings (brass bits moulders buy) are BSPT.

As Pat said, they all fit (Thread angle difference), just takes more grunt to seal!

Cheers


Harry