had a conversation today with a "REAL" (23 yr.old) custom fabricator . I commented that I had made custom oil lines for my old (1981) Harley . showed him a picture , and showed him braided stainless flex lines I had made on my P/U truck . (i'm a retired mil. & civ. acft. mech. over 40 yrs. in aviation maint.) . the lines he saw were full S/S including fittings . I said when new engine went in my 91 R/S it would have a couple . he was quick to inform me that "REAL" AN fitting's are red & blue . (i'm never too old to learn) anyway I asked him what AN stood for . I was informed red & blue fittings . I then thanked him & laughed . see us old pharts are never too old to learn "NEW" things . cheers !!!

 

I thought AN was a military size, // Army/ Navy.??

 

AN fittings don't have to be red and blue (although they usually are), they come in other colors. And yes, AN stands for army/navy.

 

I think I learned something.

 

maybe I should been a little stronger with my sarcasm in the OP . fact is AN fittings sold from summit , jegs , etc. are red & blue for the "eye candy" effect . AN fittings can be most any color . the color is the anodize coating on the aluminum . that said AN fittings ARE good . the color has NO effect on function . (does an item function better if it's chrome ?) once again the red & blue colors are for the "eye candy" effect , nothing else . good luck .

 

Everyone is correct in that they are military specification fittings dating from WW II, but the AN stands for "Aeronautical and Navy".

 

I'm glad you have finally learned that us young bucks always know best UNCLE TOM

on that note, my buddy had an IROC that he swapped to carb, used AN fittings to run fuel lines to the carb(Red and Blue naturally)

a kid we knew swore up and down that my buddy was running "NAWS" because he saw "RED and BLUE fittings everywhere"

 

I think I remember reading somewhere that the difference between the Red and Blue is kind of like a dummy system for maintainers. Perhaps some of the ex or current military can shed some light on this?

It was some time ago I heard this, and am not sure if it is true or not, but Blue is serviceable meaning it's OK to remove those fittings for normal maintenance procedures where as the Red fittings were not to be touched unless they were being replaced or something like that?

 

Now I learned something new.

 

Red means don't touch, it is a fixed fitting, blue is the move-able part of the fitting. Makes it a no brainer when removing lines. Of course you can get them in all different colors now, so some of that goes out the window.

 

AN for Army/Navy. It's an old military terminology used to determine tubing sizes in 16 of an inch. -8 is 1/2", -6 is 3/8", -24 is 1-1/2" etc.

AN normally means aluminum fittings while JIC normally means steel fittings but other than that, they're exactly the same with a 37 degree flare seat.

I have red, blue, black, and chrome AN fittings all over my engine. For some people, color coding means everything. For me it was whatever fitting was in stock to do the task I wanted it to do. I even bought a 37* flare tool to make some custom hard lines.

 

AN as previously stated stands for Army Navy, and the specifications AN fittings allowed for steel, stainless, aluminum, and titanium. Titanium was not allowed for oxygen or drinking water.

JIC is the SAE watered down version. JIC fittings generally are interchangeable with AN however they allow looser tolerances than AN and can be up to 40% weaker.

AN fittings were a multi character code, we all know the 8 refers to size, but it could be preceded by an L to designate it was drilled for lockwire, and after the size there would be a letter for material desination and possible an N to state that was ry lube on the threads (only on stainless)

JIC fittings are color coded to the material.

AN.............Material.....................JIC (SAE)
D(obs).......Aluminum (2014, 2024)..Blue
W.............Aluminum (7075)..........Brown
none.........Steel (1137, 4130).......Black
undefined...Copper......................Cadmium
J...............Stainless (304)............None
K..............Stainless (316)............None
T..............Titanium 64A1)............Gray

 

^^Thats exactly what I was gonna say^^

 

While the Army wasn't part of the naming of the AN fitting, they also used them. The newest designation for the military is the AS fitting. The AS stands for Aerospace.

Here's a little more information on AN fittings history from Parker.

http://www.x-h2o.com/showthread.php?...the-AN-Fitting

 

Strictly speaking, if it is not an aircraft fitting, it is not technically AN even if it has a 37 deg flare. To receive AN specification, the tolerances have to meet certain standards as do the metals used to create the fittings. IIRC the manufacturer has to have a record of all of these things -going back to the raw material used, source, etc
If you compare actual aircraft fittings to some of the fittings (all of them? All the one's I've seen anyway) sold by the auto aftermarket, you will immediately notice a significant difference in quality. I'm not even sure they would work with real aircraft hose. The automotive braided hose I've seen is really nothing like aircraft hose. It is much thinner.
If you want actual aircraft hose and fittings, be prepared to spend a whole lot of money. They are not cheap. They are also complete overkill for a car. IIRC I would proof test medium pressure rubber at 1500 psi and iirc their burst pressure was supposed to be 3000. High pressure teflon proof was 3000.

There might be some obscure reason for the various colors but in my experience, the colors only denote which manufacturer made them.

The two main manufacturers I would see was Aeroquip or Stratoflex. Medium pressure rubber Aeroquip is usually red/blue and stratoflex is yellow/blue. For teflon (medium and high pressure) lines the fittings are all stainless and thus have no color.
There are also other color combinations that I have seen such as red/black and yellow/black and I'm not sure which brand those are or if they were one of the above two brands.
On the aircraft I worked on, the AN fittings were used for either Fuel or Oil. Hydraulics always used MS fittings which is a flareless compression fitting.

The only color fitting that I recall meaning anything was green which was technically for oxygen. Since the majority of aircraft I built lines for were unpressurized, we used green just like any other color. The only green fittings I remember were MS though, not AN.

They might have some different guidelines in the Air Force for heavy aircraft or in the civilian sector.

My experience is USMC and I built hoses/tubes for just about everything the Corps flies. 5 years in aircraft hydraulics/pneumatics shop + 4 years airframes/hydraulics on Hueys and Cobras

 

They are not as strict when it comes to fittering tolerances, however saying they are 40% weaker is somewhat wrong. For example, I do a lot of hydraulics and use JIC fittings rated for 4000psi.

Find me an AN fitting rated anywhere near that.


-- Joe

 

Would you feel comfortable using just any JIC fitting in that application?

 

Although you would think Parker would know, but the Air Force didn't exist as a branch until 1947. From the period of the tube and fitting standard it was Army Air Corps, So I'm inclined to believe it was Army Navy.

 

I'd use JIC fittings rated for 4000psi. That's what I use on my skid steers, excavators, log splitters, etc.

AN fittings are not rated for such pressures and would cause an obvious safety issue.

-- Joe

 

I believe Aeronautical-Navy is correct.

Bureau of Aeronautics was in charge of designs, standards, and procurement from around 1921 to 1959.

-- Joe

 

Army / Navy aeronautical standard. The Nay portion was controlled by their Bureau of Aeronautics through 1959 when they were absorbed along with Bureau of Ordnance into the new Bureau of Weapons Systems