Styles of compressed air fittings

92saturnsl2

92saturnsl2

Joined
Mar 2, 2004
Messages
4,101
Location
Kentucky
I'm redoing some of the air plumbing in my garage and at the hardware store I noticed there are several different styles of air fittings. When I did my lines originally the store I went to only had one style, so that's what I got which ended up being "M" style, which I'm pretty sure is most common as I see that style regularly in other buildings. But there's a T, V, ARO, and a couple others I believe.

Does any style offer advantages over the other? I don't do anything particularly heavy duty and the fittings I have flow plenty of air for what I use it for.

But it does annoy me that the quick connect fittings I have aren't as reliable as I'd like. They seem to work okay for a few months but I notice that eventually they begin to leak if there's slight pressure on them or the hose twists. Replacing the quick connect coupler always fixes the problem but this is a headache I'd like to avoid. Curious if one of the other styles might be more resistant to this type of wear, or have a more secure connection that might be longer lasting.

Any info on the strenghts / weakness of the different styles would be helpful, or are they all created equal?
 
I thought the common types were just called "industrial", "automotive", and some other type (without Googling, the name escapes me at the moment). Problem is, they're partly interchangeable although they don't fit or connect 100% perfect. It could have been the coupling I was using that was the problem too as I'm sure they're for specific types too. If I recall what happened, I had bought the various fittings in a set so obviously they matched. Later, I had to replace a single fitting and ended up buying the wrong type (not even realizing there was a difference).

I Googled this stuff at the time and don't recall that one is "better" than the other. They're just different.
 
I'm an industrial supplier to some major trucking companies, Milton style fittings is so far the most popular with all of my customers. I have one account that absolutely DOES NOT like quick disconnects.

As far as weaknesses, I have not had any complaints. The only part that I've seen wear out more than anything is the male quick connect fitting, it gets worn out from repeated disconnects.
 
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Milton "M" style are the longest lived, If you don't need high flow, That's what I would recommend. The Milton "V" style is pretty good but not as long lived. I've used "M" style on my Trans benches for over 25 years with great results. The only tool I use that really requires "V" style fitting is a Proto 3/4" Impact & don't use it all that often.
 
The one on the left is common in auto repair shops. The middle with construction guys. I have never seen the one on the right

Screenshot_20200621-213819.png
 
The one on the right is the 1/4'' ARO fitting which 99% of NZ shops use....except where I work, where we used the 3/8'' ARO.
 
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I've been converting all my fittings to the high flow style. There is a real difference in performance and speed.
 
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I'm using the Milton V style/ high flow. I think a box was 10 was around $12 on eBay. The quick release fitting was just under $10.

Somewhat annoying to have unique fittings to everyone else. I've had to swap fittings a few times so far. I need to especially make a normal to high flow adapter with 3' or so of hose and vice versa.
 
I have my air system broken down into multiple parts, one uses M fittings 3/8 hose with filters and oiler for tools. The other is V, 3/8 hose all sorts of filters and cooler but no oiler for spraying, tire filling, blow gun use. There is also 1/2 line from both oil and clean sides for higher cfm 1/2 hose.
 
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Curious, do all the fittings have only a 1/4” or smaller interior?

Im setting up air in my new garages, and plan to use Milton V style high flow. My 15scfm compressor has a 3/4” outlet, so I’m just running 3/4” line up to the point where I want a regulator. I bought one of these:

2F203918-9FF1-41DD-86B0-B6932E9F8876.jpeg


But noted on the back, fwiw:

DB734067-8BA6-4856-B62B-F67FC39ADF96.jpeg

Maybe it doesn’t matter, but seems like 3/8 fittings are just for convenience at that point. The fitting can handle more free air than my compressor pump can handle, I’m just not keen on having a smaller than necessary orifice in a pathway that I’ll keep as wide open as possible, as far as possible. My garages are over 100’ long, and I can see wanting a hose of at least 50’ after this. I’m not hard plumbing throughout the building.
 
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Did Milton sell out? I've noticed they are no longer carried anywhere, and the miltons that were carried were made in USA?

I'm on Milton site and they have the anodized "color code" cheapies, and the brass couplers are not made in U.S.? The Air Chuck Inflator Gauge is made in U.S.

Looks like they have outsourced most of their line.
 
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Vern_in_IL said:
Did Milton sell out? I've noticed they are no longer carried anywhere, and the miltons that were carried were made in USA?

I'm on Milton site and they have the anodized "color code" cheapies, and the brass couplers are not made in U.S.? The Air Chuck Inflator Gauge is made in U.S.

Looks like they have outsourced most of their line.
Click to expand...

The fitting I showed just above was made in Taiwan. Older ones I bought, I think at Northern Tool, were US made.

I just got a filter and regulator from them, and it’s all made in USA.
 
Here is a comparison between my GuardAir High Flow, Milton V, and something brass I got at Lowe's and then threw away. Small differences may seem small, but remember basic geometry: volume goes up by 4x the increase of the inner diameter. On my GuardAir JetGuard air gun, with the trigger stop set wide open, it can empty a tank quickly. When "going big" it is important to replace all the connectors in the path, especially the first one on the tank. One cheap quick-disconnect can ruin everything.

I currently use the GuardAir's on everything on my big compressor in the garage, and the Milton V's on the 1/3HP-10gal in my hobby workshop. The GuardAir's are kind of pricey. The Milton V's are a bargain.

MiltonVvsGuardAir.jpg
 
JHZR2 said:
Curious, do all the fittings have only a 1/4” or smaller interior?

Im setting up air in my new garages, and plan to use Milton V style high flow. My 15scfm compressor has a 3/4” outlet, so I’m just running 3/4” line up to the point where I want a regulator. I bought one of these:

But noted on the back, fwiw:


Maybe it doesn’t matter, but seems like 3/8 fittings are just for convenience at that point. The fitting can handle more free air than my compressor pump can handle, I’m just not keen on having a smaller than necessary orifice in a pathway that I’ll keep as wide open as possible, as far as possible. My garages are over 100’ long, and I can see wanting a hose of at least 50’ after this. I’m not hard plumbing throughout the building.
Click to expand...

That Milton V quick disconnect fitting will flow a LOT more than anything non-High-Flow. It is also "mostly compatible" but may be a bit leaky when used with other type connectors.

The inside diameter of your 3/8 hose 1/4" NPT fittings can be drilled-out some, if it amuses you. I have one such hose that I experimented with. It helped my impact gun a bit, but not as much as replacing a badly constricting standard quick-disconnect, or replacing all the fittings with High Flows. Then I got a bigger tank+compressor and it really didn't matter any more... but I'm already invested and fully converted to High Flows, not going back.
 
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