View Full Version : Thread details

06-16-2013, 09:40 PM
I am trying to get some details on this fitting so I can find or make an adapter.
It's on an AC vacuum pump. I am wanting to use it for vacuum bagging not AC work.
It seems to be called several different things but cannot find a drawing, Machinery Handbook did not seem cover it.
I have seen it called 1/2" Acme or R12 fitting. Or one place called it a 1/2" FIPS

It looks like a non tapered pipe thread with a Oring seal.
Looking for an adapter to something more standard like a 1/4 NPT.
I tried a 1/2"NPT and it did not look to seal properly.
I have located one online source that sell the Robinair 6 CFM for vacuum bagging and sells an adapter for it but it says its 1/2" NPT to 1/4" NPT.
I shall call them in the morning and go for a couple hour drive if thy have it.

Any ideas.

06-16-2013, 10:04 PM
Dave it looks to me like a standard 1/2" 45 flare male fitting.
Most automotive supply stores usually stock a large selection of Weatherhead brass fittings, check there first as I'm sure that they will be able to source your fitting.

Here's a random link to these fittings.

If you do a quick search you'll be able to download Eaton's full Weatherhead fittings catalog

06-16-2013, 10:10 PM
I am not sure which end of the fitting you are talking about and cannot tell the size from the picture, but if it is 1/2" the top is 1/2 SAE. The bottom is another matter. Hard to tell without taking it out. Could be an "O" ring base fitting but because it is brass not very likely. You may find the the bottom of the brass T is 1/2" NPT or the other brass fitting it is screwed into could be a special adapter and the other end of the T could also be 1/2" SAE. male also.

06-16-2013, 10:13 PM
Could be a 45* 1/2 flare fitting on the top end-


And if it's 37* then it could be a JIC male flare-


The bottom could be a Male O-ring boss connection-


I say "could" because mankind has invented a lot of different schemes to move fluid and gas around and we show no signs of letting up:rolleyes:

06-16-2013, 10:33 PM
I think it is a standard 3/8" flare fitting, you can get adaptors at any plumbing supply. Or if you have a flare tool get a 3/8" flare nut and flare some tubing and adapt from the tubing.

06-17-2013, 12:17 AM
What dia? What thread pitch? It would help to know.

Where in Surrey are you? Our shop is on the Bypass and we have a bunch of miscellaneous fittings we could compare it to--might be able to find the right one or at least identify what you've got...

06-17-2013, 01:05 AM
Thanks for the suggestions. I will do some measuring tomorrow. It's my understanding the AC fittings are not SAE. Kieth, I am in North Surrey near Delta border. PM me some contact info and I will contact you. I went to Green Line on Friday without the unit just a picture and got the brush off. Been going there for years and the bubba I got was not very helpful. Having a selection of fitting would be awesome.

06-17-2013, 01:35 AM
Let us know what you find, but I'd be willing to bet it's an SAE flare fitting. Hard to say exactly what size without dimensions.
Just for reference below is a link to a pic of an SAE 1/4" flare female to 1/2" ACME male. I'm sure you can see the difference.


michigan doug
06-17-2013, 01:25 PM
Yes, that is a bone stock flare fitting.

Buy a flare nut at any plumbing/hardware store, and a flare tool (less than twenty bucks), a piece of copper tubing and you're in business.



06-17-2013, 03:28 PM
DF Miller I agree with Willy. Standard flare fitting. Just checked the output on my vacuum pump and it has a T with a 1/2 inch acme, this fitting and another one that I have never used.

06-17-2013, 11:40 PM
Finally got around to measuring fitting. Its got a 3/4 x16 thread so its a 1/2" SAE 45 flare. Everyone was correct.
Went south today and fought the 60 minute border lineup each way and picked up the magic fitting a the Vacuum bagging specialty shop.
Installed it and it holds vacuum. Not the correct fitting but it seals. 1/2 NPT F on one end and 1/4 NPT F on other. Loose fit but when tightened seals fine. Just don't tell the fitting it should not work. ;-)

Laminated a piece and left pump running overnight. Seems all is good.
Thanks for everyone's help.
Learned a few things.