View Full Version : Air fittings profusion..... What's "standard"?

J Tiers
03-12-2011, 04:00 PM
I seem to have several "standard" air fittings on various hoses and devices. Many of them do not interchange.

I have Foster fittings (no number) , I have Hansen series 1000 fittings, which "almost fit" Foster.

I have Milton 777 fittings, and I have another type which is "almost" a Foster type, but does not in any way fit.

What's the "most common" type? I'd sure like to have on my stuff whatever is "most likely" to fit another compressor, and have other hoses etc "most likely" fit mine. I'm OK with swapping out lots of fittings if necessary, or even having doubles, if required

The two oddballs out seem to be these:

The bottom one is a Milton 777, which fits nothing at all around here, and the top one is something probably chinese, which fits a lot of things, but NOT the Milton, Hansen, or Foster. Of course it is on the compressor.


03-12-2011, 04:09 PM
It may be a regional thing , but around here the Milton "M" style seems to be the most popular by a wide margin.

03-12-2011, 04:10 PM
It all depends. Tru-Flate seems to be the car repair/gas station standard, and happens to be what I use. Beyond that, I have no idea. There is one called "industrial interchange," but whether it is significantly interchangeable or just an optimistic name I don't know.

03-12-2011, 04:28 PM
Princess auto here sells 'universal' female couplers, That do M, T, etc

Iv got mainly M, but I think im actualy using T style female couplers? And some universals...

Not exactly sure now that I think about it.. I know some of my couplers (usally) have the quick release 'locked' in the back position with a hose removed, I think thats type T (Hence why I bought em, conviance)
Pertty sure the universal don't do that... Although im not sure if T and M are compatable, Or if these are just good M couplers.

That noted, the universal couplers do tend to leak a little on M fittings if the fitting as a lot of angular stress on it (Like the coupleing comming horzontaly out, and a regulator or heavy hose pluged into it)

Ohio Mike
03-12-2011, 04:34 PM
It may be a regional thing , but around here the Milton "M" style seems to be the most popular by a wide margin.

Same here.

Bill Pace
03-12-2011, 05:14 PM
Another "M" here -- all my stuff is "M" and seems to be, by far, the most common in the various display racks at the stores

03-12-2011, 05:27 PM
The Milton has an auto shop type one and an industrial shop type. The way it was explained to me by the owner of the auto parts place. I believe that there is a difference in the length of the last part on some short, long and longer. I have shortened the long ones and they work with no problem. Along with a difference in the first knuckle up from the end like in your picture. Then there is the other brands are different enough that they won't fit any but their own brand.

HF seems to fit the Milton ones for auto shops.

Then they have some that are for 1/2" connections and it starts all over again a real pia if you aren't looking when buying.

J Tiers
03-12-2011, 05:52 PM
Say which?



These seem "M-T" of meaning to me, as the stuff I have is not described that way.

The "M" seems most like the upper one in the pic, but I already know about "looks like" when it comes to couplers. Meaning that it has no meaning. It does seem to me a "MIL" standard, for whatever that means.

The bottom seems to be also known as a Milton "A", or possibly a different one.... Seems unpopular, which is no doubt why I have a bunch of them from a toolbox I bought somewhere at a sale :rolleyes:

The Milton T seems to be like the "auto shop" variety.


Sounds like the "M" is the winner here, and it seems to be the style I already have on the compressor.

The autobody shop type ("T"?) looks a bit more robust and less likely to be damaged..... and presumably is fairly popular also.


Thanks for the narrowing-down of the choices, anyhow.

03-12-2011, 05:58 PM
Jerry, your "777" refers to the fitting being an "A" style 1/4" NPT male plug. 775 would be the "A" style 1/4" NPT female coupler and 778 would be the "A" style 1/4" female plug, at least according to Milton.
The bottom fitting in your pic is an "A" style and the top fitting appears to be an "M" style. I use the M style myself. A lot of people like the extra support the L style has, they claim they last longer before leaking.

Handy dandy little chart...

Here's an interchange chart from Milton

03-12-2011, 06:09 PM
In the tool business for twenty-five years. Sold quality nipples and couplers.
But stocking them was a constant head-ache. A mechanic changes shops, change nipples. I quit trying to standardize my stops. "Those are the ones daddy used and I not changing" I guess it is something we will have to accept.

J Harp
03-12-2011, 06:12 PM
I have some HF female couplings which the fittings on my air hoses wouldn't fit into. I chucked the male fittings and took about three swipes with a file on the diameter back of the groove and they fit.

03-12-2011, 06:26 PM
Standard is what ever "YOU" have in your shop.


J Tiers
03-12-2011, 06:28 PM
The "handy-dandy chart" seems to me very helpful indeed.

I think it will sort out what I have here very nicely. Thank you very much.

I was looking for "Milton", but got pages of dealers, instead. Didn't look for Milton "Industries" though. Only name I had was "Milton".

03-12-2011, 07:08 PM
I think of air nipples as either automotive or industrial. I use industrial.

Male air fittings are kind of generic. Female air fittings vary a great deal in quality. I have a lot of hoses which came from Boeing. To attach something to a female hose end, you just need to push. I really like those kind.

I have found that cheap fits-all female fittings often leak badly.


03-12-2011, 07:10 PM
Not that it makes any difference but "we" used to deliberately have two styles that would not interchange within the shop.

One style for the lines that had oilers built in and another style for those lines that were used for paint only (no oiler in-line and a bit more prep of the air).

Got used to going out and buying all new fittings to match whatever the new workplace shop had...

bob ward
03-12-2011, 07:33 PM
Down here the Nitto style air couplings have become the defacto standard.


03-12-2011, 07:45 PM
I use the Milton 777 (type A) because both the Mac and Snap-On tool trucks carried only them when I was a MC mechanic. If they had some thin else, I probably would have picked that. The Milton type M is the series sold by Sears and is the most common I see on job sites.


03-12-2011, 08:28 PM
It's like JoeLee said, the standard fitting is what your using in your shop or where you work.

That means, there is NO standard.

Everytime I changed jobs I had to change air coupling fittings. I ended up with a crap pot full of them. When I retired I decided which one I liked and threw the others away.

03-12-2011, 08:31 PM
I use 3/8 true-flate all over my shop, except the blow guns, they are mounted directly to dedicated small hoses so they don't get lost.

03-13-2011, 03:59 AM
Both the automotive shop and the welding shop at the school have M fittings, but they're NOT interchangeable. No tool from the welding shop will fit the hose couplers at the auto shop, and no tool from the auto shop will fit the hose couplers at the welding shop.

You need to look closely at the male fittings to see the difference.

I've even gone to the local Lowes store, and I found some of their M female couplers will not fit their M male plugs. I wonder how many wasted trips that's caused.

big job
03-13-2011, 07:03 AM
For years and years this was a major threat. Why cant there be a standard.
Guess not UNTIL one day I went to my local Napa . On the counter special
are the female (on the air hose) that fits all -long short -fat skinny. Very
nice knurled. Just push in- theres one click and the second click turns on
the air. To disconnect slide first ring (shuts off air) second click releases
this chuck from the tool. Selling for about 6 bucks. I have never seen this
anywhere. I conclude somebody locally is making these. They are
extremly well made. You might check Napa or think about making one up.
I am thinking they may have a series of O rings I dont know and I dont
know how it comes apart? all i know they work perfectly.

03-13-2011, 08:28 AM
i have boxes of fittings. i change jobs got to change fittings. even some places you change buildings you change fittings. where i work now there are diffent fittings all over the place.

03-14-2011, 06:02 PM
Universal Fitting = One you have the least of.......:rolleyes:


03-16-2011, 03:55 PM
I always tried to use fittings different from the shop "standard" and made up short whip hoses to adapt. kept other people from useing my air tools