Metric Pipe Thread ?

[thays]

Are British tapered pipe threads considered metric?
At work, they want to make some ISO 7-Rc 1 1/4 tapered threads and they are calling them metric and use a 60 degree insert. I'm thinking they need to use a 55 degree insert (BSPT).

[john_100]

Hi thays ,

BSP 55 degrees , metric 60 degrees is not BSP



does this link help ? :-

BSPT Threads - British Standard Pipe Tapered Threads Whitworth Tapered Pipe Thread DIN 2999 Brass Nuts Brass Bolts Brass Fasteners Brass Nut Bolts Brass fasteners

and BSP Threads British Standard Pipe Threads Whitworth Pipe Thread DIN ISO 228 Brass Nuts Brass Bolts Brass Fasteners Brass Nut Bolts Brass fasteners

or http://www.hahnreiter.de/docs/seite_14-15_en.pdf


John

[thays]

John
Thanks for the reply.
The print I have calls for ISO 7-Rc 1 1/4 threads and notes at the bottom of the print call for Metric.
I can't find anything on the net about tapered Metric threads and don't see any gages or inserts.

[john_100]

Hi Thays ,

thats another standard europe has messed about with

I had not heard of a metric BSP thread before , but it had to come

Pipe Threads where Pressuretight Joints are made on the Threads - ISO 7-1

http://www.hahnreiter.de/docs/seite_14-15_en.pdf

British standard pipe thread - Wikipedia, the free encyclopedia


John

PS my searching for ISO 7 or ISO 7-1 points to Whitworth based threads , RC indicates internal taper thread
and so far I've not found any thread gauges

one thing I've come across is imperial screws with non standard hexagon heads due to the use of the nearest metric stock

[thays]

John
Thanks again for your help.
When I got to work today the person that had drawn the print was thinking the bitish threads he wanted were metric. I just read somewhere that many people think because British threads are foreign they are Metric.

[juergenwt]

John - go here: British standard pipe thread - Wikipedia, the free encyclopedia
and here: http://www.hahnreiter.de/docs/seite_14-15_en.pdf

[john_100]

Hi juergenwt ,

I did find those links while looking for any diagrams for metric fittings , eg :--

http://docs-europe.electrocomponents...6b80ff4cd5.pdf

it looks like whitworth based pipe threads are used on fittings make to
metric sized components

John

PS this reminds me of a drawing (print) from GEC switch gear

the drawing was of an adaptor used to fit an old imperial sized switch
in to a new metric sized switch box

the original drawing had been metricated by changing the dimensions of the brass from 1/4" x 1/2" to 6 mm x 12mm !!!

so you ended up with a 3/4" x 12mm x 6mm brass block with two tapped
holes , one imperial BA and one metric !