The passing of British Standard Pipe Threads 1

[vagulus]

As one whose working life involved frequent use of BSP Threads I have yet to come to terms with BSP's replacement in a Metric World. I am looking for a chart which gives me Standard BSP sizes down one side and their Metric Replacements down the other.

I'd also like to know if a 15mm BSP thread is simply a re-named ½"BSP thread.

Would someone please help me out?
Thanks

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Artificial Intelligence is no match for Natural Stupidity

 

[XL83NL]

EN 10226 maybe?

https://www.ring-plug-thread-gages.com/ti-spec-EN-10226-1.htm

Huub
- You never get what you expect, you only get what you inspect.

 

[LittleInch]

It seems quite complex, but I believe you are correct, i.e. a 15mm BSP is the same as a 1/2" BSP. difficult to find a table like you want as nominal versus actual is quite different.

The thing I've found though is that some 15mm fittings seem to be just a little bit different in ID and OD to 1/2" so don't fit as well as you hope.

You can get imperial BSP to metric compression fittings etc and I would definitely use that.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[vagulus]

Thanks folks.

LittleInch has hit the nail right on the head.

Consider this bit, ... 15mm BSP is the same as a 1/2" BSP. difficult to find a table like you want as nominal versus actual is quite different.
The thing I've found though is that some 15mm fittings seem to be just a little bit different in ID and OD to 1/2" ...

Engineers are normally meticulous They like things to be correct and accurate and all those other unfashionable, annoying things. Something like this is usually thoroughly rationalised.

Why have we allowed this change from Imperial to Metric to escape Engineering Rigour?
What do we do about it?

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Artificial Intelligence is no match for Natural Stupidity

 

[3DDave]

Almost always the reason is money. As long as there is equipment that uses the old standard there will be tools and parts to repair it, so there will be people making those tools and parts and so on. Why then become incompatible if a new extension is added to an existing system? Since anyone doing this work has those tools and parts, why throw them out while they remain useful?

See

https://allplumbingonline.com.au/pages/size-conversion

The sizes are lies all the way down.

To fix it, stop using any form of BSP and create a new series, to add to the many that already exist. And then remove and replace the majority of installed components and take all the taps and dies and spare parts out of circulation. Simple.

 

[vagulus]

Alternative solution, 3DDave:

Use existing (old) manufacturing equipment; retain existing BSP plant; multiply inches in the dimensions by 25.4; redesignate traditional BSP sizes to "Metric Nominal" sizes; display size transfer charts (like the one you linked to - thanks) in all design offices and workplaces; never refer to Imperial BSP again.

Simple (and it wouldn't cost anywhere near as much ).

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Artificial Intelligence is no match for Natural Stupidity

 

[3DDave]

Not really - unless you want a 47.803mm metric fitting, for example.

Like Hotel California, you can check out any time you like, but you can never leave. What made it BSP wlll remain.

 

[TugboatEng]

Why change? Is their an availability problem? I have found SAE and BSPP fittings, and Swagelok + clones to be superior to metric fittings in all cases in both availability and emissions. NPT is over applied but there are some really fantastic sealants available for it that cover up its inadequacies nowadays.

 

[XL83NL]

I may have misread the OP.

What actually is 15 mm BSP? What does the 15 mm refer to? Never heard of, while all our plants (which are destined for Europe) are full of BSP.
Is this some new ISO thread standard for metric designated BSP?

Huub
- You never get what you expect, you only get what you inspect.

 

[3DDave]

XL83NL, See the page I linked to. It has all the gory details.

 

[XL83NL]

Thanks Dave

Huub
- You never get what you expect, you only get what you inspect.