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lazlo
05-25-2009, 08:08 PM
I'm overhauling an Eisele (German) pneumatic cold saw, and it has a cracked male branch tee on the air intake, where the male threaded section broke off in the electronic solenoid opening.

It's about a 1/8" diameter, but a 1/8" NPT doesn't want to thread into the solenoid without forcing it. I just looked up the part number on the web, and it's an "Origa" solenoid, and the datasheet lists the port as "G 1/8".

That's a hard term to Google, and the Black Vitruvian Man Book doesn't list it. After spending awhile in Machinery's Handbook, I found a comment that says that British Standard Pipe Threads use designations that start with "G", followed by the orifice size.

So it looks like "G 1/8" in BSPT is 28 TPI, Whitworth. Does that sound right? Is it possible that Eisele, a German company, would use a British Witworth pipe thread??

gda
05-25-2009, 08:22 PM
That is an ISO designation thread, very common in Europe.

From the FESTO web-site

What is the difference between a G-thread and an R-thread?
G-threads have a cylindrical form in accordance with the EN-ISO 228-1 standard. R-threads have a conical form in accordance with the ISO 7-1 standard. In the case of a thread of size 1/8", for example, the threads are specified as G1/8 or R1/8. Male G-threads (cylindrical) can only be screwed into female G-threads. Male R-threads (conical) can be screwed into female G or R-threads.

Follow this link for the dims.

http://www.festo.com/cms/en-us_us/4298.htm

gda
05-25-2009, 08:24 PM
That is an ISO designation thread, very common in Europe.

From the FESTO web-site

What is the difference between a G-thread and an R-thread?
G-threads have a cylindrical form in accordance with the EN-ISO 228-1 standard. R-threads have a conical form in accordance with the ISO 7-1 standard. In the case of a thread of size 1/8", for example, the threads are specified as G1/8 or R1/8. Male G-threads (cylindrical) can only be screwed into female G-threads. Male R-threads (conical) can be screwed into female G or R-threads.

Follow this link for the dims.

http://www.festo.com/cms/en-us_us/4298.htm

This will also help

http://en.wikipedia.org/wiki/British_standard_pipe_thread

lazlo
05-25-2009, 08:53 PM
That is an ISO designation thread, very common in Europe.

G-threads have a cylindrical form in accordance with the EN-ISO 228-1 standard.

Follow this link for the dims.

http://www.festo.com/cms/en-us_us/4298.htm

OK, so the G pipe threads are not tapered, like an American NPS, but if I'm reading the Festo document correctly, the G 1/8 is in fact a British Standard (Witworth) Pipe Thread. It doesn't say as much on the Festo web page, but the 28 TPI, and 9.728 mm major diameter (ain't Metrification great? :)) match Machinery's Handbook spec for the BSPT 1/8.

Thanks gda!!!

SDL
05-26-2009, 07:03 AM
OK, so the G pipe threads are not tapered, like an American NPS, but if I'm reading the Festo document correctly, the G 1/8 is in fact a British Standard (Witworth) Pipe Thread. It doesn't say as much on the Festo web page, but the 28 TPI, and 9.728 mm major diameter (ain't Metrification great? :)) match Machinery's Handbook spec for the BSPT 1/8.

Thanks gda!!!

Thats because the europeans prefer the ISO designations, but many here still refer to BSP British Standard Pipe Parrelle and BSPT British Standard Pipe Taper.

Steve Larner

boslab
05-26-2009, 07:50 AM
1`/8 bsp t or p will fit, if p then a bit of the old ptfe tape and the white festo poly washer
mark

mbensema
05-26-2009, 08:13 AM
G fittings are BSPP with Whitworth threads with the 55 degree thread angle and is pretty much standard on anything coming out of Europe. These pages gives you all the dimensions you should need for the male fittings.

http://mdmetric.com/tech/bsppthreadspecs.htm

http://mdmetric.com/pdf/Thdfrm2.pdf

You can get the copper seals for these fittings at a Swagelok distributor.

lazlo
05-27-2009, 02:31 PM
Thats because the europeans prefer the ISO designations, but many here still refer to BSP British Standard Pipe Parrelle and BSPT British Standard Pipe Taper.

Guys, thanks for all the replies!! I was able to order the correct "ISO-G" fittings from MSC last night during the 35% off sale.

I can finally say that I own a machine with a Whitworth thread ;)

Pulling the responses together, if anyone on the Left side of the Pond is looking for these fittings, MSC, McMaster et al calls the BSPP (non tapered) Whitworth fittings ISO-G, and the BSPT (tapered) fittings ISO-R. Seems like the tapered ISO-R fittings are much more prevalent.

By the way, there are also true Metric pipe fittings, so I'm surprised that a German machine tool manufacturer would use British Whitworth pipe fittings instead of Metric.

Mark McGrath
05-27-2009, 03:21 PM
Quote
"By the way, there are also true Metric pipe fittings, so I'm surprised that a German machine tool manufacturer would use British Whitworth pipe fittings instead of Metric."
___

It seems to have escaped some of you guys in the colonies,but BSP was adapted as the standard for pipe threads by ISO and every country in the world except USA and one other small country somewhere._A lot of years ago now.______________

lazlo
05-27-2009, 03:43 PM
It seems to have escaped some of you guys in the colonies,but BSP was adapted as the standard for pipe threads by ISO and every country in the world except USA and one other small country somewhere.

That doesn't explain why there are ISO standard Metric pipe threads?

Parker, Festo et al all stock "ISO-M" pipe fittings, which are ISO standard pipe threads:

Metric Thread Standards
M - Metric Screw Threads M profile

Applicable Standards

* ISO 261 ISO GENERAL PURPOSE METRIC SCREW THREADS - GENERAL PLAN
* ASME B1.13M METRIC SCREW THREADS: M PROFILE
* FED-STD-H28/21 METRIC SCREW-THREADS

John Stevenson
05-27-2009, 04:20 PM
There might be a metric thread but doesn't mean to say anyone uses them other than the Japanese, As mark says the BSP / gas threads have been around for ages and are in use all over the world.

.

lazlo
05-27-2009, 04:45 PM
There might be a metric thread but doesn't mean to say anyone uses them other than the Japanese.

There's a JIS (Japanese) pipe thread standard too. Parker and Festo stock those as well :)
And just to make things more confusing, the BSPP, BSPT pipe threads have Metric orifices. Yes, they have an Imperial thread pitch (28 threads per inch), Imperial Major and Minor diameters (G 1/8 is 1/8" OD), with an English thread form (Whitworth) and Metric tubing :rolleyes:

So there's the US NPS/NPT standard, the British BSPP/BSPT standard, the ISO-M (Metric) pipe thread standard, and the JIS standard. It's amazing anything works. :)

By the way, the British Pipe Threads are almost unheard of in the 'States...

What do the Canucks use? My Excello has NPT coolant drain ports...

gda
05-27-2009, 06:11 PM
Don't forget AN (Army Navy) fittings.

Limy Sami
05-27-2009, 06:54 PM
Quote
"By the way, there are also true Metric pipe fittings, so I'm surprised that a German machine tool manufacturer would use British Whitworth pipe fittings instead of Metric."
___

It seems to have escaped some of you guys in the colonies,but BSP was adapted as the standard for pipe threads by ISO and every country in the world except USA and one other small country somewhere._A lot of years ago now.______________

Yes, and don't we have some fun when we get US pipe threads over here,.......... John Deere are very good at combining 2 if not 3 standards on the same machine.

Lew Hartswick
05-27-2009, 07:21 PM
They say thats the wonderful thing about "standards" , there are so
many of them. This has been a case in point.
...lew...

oldtiffie
05-27-2009, 11:47 PM
Lazlo.

I can understand the frustration here, but we have addressed this sort of issue before.

The Europeans quite often use established customs and uses of "industry standard" (usually, but not always US) "as is" and "hard convert" the inch dimensions into metric and endorse it as an ISO standard expressed in metric form in exact metric equivelants.

Three which come to mind are:
- 1/2" and 1/4" square drives in sockets and ratchet wrenches;

- standard (US) milling machine spindle tapers:
http://i200.photobucket.com/albums/aa294/oldtiffie/machine_tapers/Machine-taper5.jpg

- BSP threads - which are in extensive use here and many of the "Metric" countries, of which OZ is but one.

I would also guess that the up-dated British Standard (BS) for British threads are expressed in "hard-converted" metric format.

Mark McGrath
05-28-2009, 04:56 AM
Not that long ago we ran 2500 pipe fittings.One end was about 2" NPT at 11.5 tpi.Where did that figure come from FFS?

Notice Tiffies post does not have a Wiki link in it.
Is this a first?
Will it continue (hopefully)?
Has he used up his lifetimes supply of Wiki links (hopefully)?

Mark.

oldtiffie
05-28-2009, 06:37 AM
And just to clarify a few issues - here it is - a Wikipedia link with BSP threads in metric form to ISO standards.

http://en.wikipedia.org/wiki/British_standard_pipe_thread

[Edit]

More grist for the mill (as it were):

Oops - nearly forgot the the whole BSP she-bang in metric form and the relevant ISO standard. Just had to get a Google link in too!!:

http://www.engineersedge.com/hardware/DIN-ISO-228.htm

http://www.google.com.au/search?hl=en&q=BSP+standard&btnG=Search&meta=

[End edit]

lazlo
05-28-2009, 10:40 AM
Notice Tiffies post does not have a Wiki link in it.


It also doesn't have any information about pipe threads, which this thread is about :)

lazlo
05-28-2009, 11:07 AM
And just to clarify a few issues - here it is - a Wikipedia link with BSP threads in metric form to ISO standards.

http://en.wikipedia.org/wiki/British_standard_pipe_thread

Thanks Tiff, GDA was kind enough to post that link on the first page of the thread. That was three days ago -- I've since bought the correct BSPP tee and installed in on the machine ;)

.RC.
05-28-2009, 08:59 PM
Metric have their own conduit thread (1.5mm thread pitch) which I think is used for steel thin walled tubing for cables and such...