AN fittings

[Anonymous-0]

What are AN fittings? I read it meant Army/Navy and they look like a flared brake line fitting. Thanks

 

[Heat Houser]

You are correct, Army Navy. The AN fittings are similar to the JIC spec in that they both are 37 deg flare with SAE threads. Most all fittings used in aircraft are AN.

 

[Dusty MI]

I've heard of the double flare like used on break lines called Navy flare.

Dusty

 

[Gun guru]

I was told that AN fittings are the SAE straight thread, IE: 1/2 Sae fitting is a 3/4-16 UNF thread with an oring for sealing.

 

[Bob]

WIKI is your friend.
WIKI AN

 

[greygoat]

AN fittings, old nomenclature,was Army-Navy,
but are now usually referred to as JIC, for
Joint Industry Conference, and are of the 37
degree angle, versis the old 45 degree angle
used in copper tubing flares and older automotive
JIC fitting are the world Aerospace standard,
and are used in aviation even by Russia and
Japan. The russians aquirred it by servicing
lend lease U.S. aircraft during WW2.
Today an airliner landing anyplace in the world
may be serviced/repaired because worldwide
aviation mechanics use the JIC system of fittings
and it has become an industrial standard.

 

[Anonymous-0]

As stated it is army=navy.After WW2 there was a large surplus of these fittings left over from aircraft.Some racer appeared at Indy using them .It caught on with hot rodders.Then the supply dried up but companies like EARLS and later RUSSEL picked up on the demand.Earl went to Aeroquip Corp and asked that they make them Aeroquip was not interested in the car market so Earl started to machine his own.Years later Aeroquip finally realized they were missing out on the large market these had become and came out with a catalog for car and bike guys.Early on they were used more only on fuel injection systems but as they grew more popular carb fittings etc.They are usually red and blue anodized aluminum.A number 6 straight cost about six bucks a 6 90 about 20. Now you have adapters for Holley carbs etc.They are reusable and very easy to service.They also have a quick disconnect type which is very expensive.The Earls catalog has charts and sizes. To adapt to say a tractor hydraulic line or whatever you start with a NPT to number [6,12 or whatever] size A-N fitting then make up the line ends.Best way to cut is mufller cutter and all dust must be cleaned out well from hose .If a line rubs on other parts it will open up the braided steel on the line and will cut you when working around it.If you want to know more get an EARLS catalog.They are a bit larger ID than Russel and I like em better myself.There is a nice product line from Russel where they are nickle plated.Do they make you go faster ,not really but look real nice.IF you are going to plumb something with these its nice to have all three catalogs as there are angles offered by some that others dont carry.Forget the instructions aboout cutting braided line with fine tooth hacksaw as it may fray the end requiring a second cut possibly shorting line.Lines should not be made up taught but have a slight S to them.Very easy to get on and off usually with an aluminum wrench to not scar the anodizing.Good Luck.

 

[KIP in MX]

Well, you are mostly correct, however, we have
Sikorsky helicopters that only use AN (we never use the term JIC) on engine fuel/oil/pneumatic systems and wheel brake lines. The hydraulic systems and emergency float nitrogen/helium systems use stainless MS flareless fittings exclusively due to 3000-5000 PSI working pressures. AN fittings are much easier to work with. MS fittings are a PIA and it's easy to cross thread them.

 

[dlplost]

AN and JIC are one in the same, both 37 deg and completely interchangable. JIC is just the newer international designation for the old AN standard.

And yes Sikorsky still refers to them as AN.
I've worked there for 35 years now.

 

[Joe(TX)]

AN, JIC, MS flare tube fittings will interchange and are 37 1/2 degree flare. The SAE are 45 degrees. Brake lines are usually inverted SAE flare.

 

[KIP in MX]

AN and JIC are identical in sizes and flare, but JIC is industrial, not authorized for aviation. Also, I've never seen an MS flared fitting, only flareless.

 

[Anonymous-0]

Thanks for the great information. You guys supplied me with all technical and even the history behind them. Thank you. Bob

 

[John Schwaner]

AN fittings are not the same as JIC fittings. See link below for article on the differences between the two.

mechanicsupport.com/articleStronger.html

They both share the 37 degree flare and basic threadform so they will mechanically interchange, but there are important differences.

AN fittings (and all other AN, MS, NAS) specifications are being replaced with AS specs (Aerospace Standard)for new design, but the AN fitting will remain in use as long as legacy aircraft remain in service.

In the "non aerospace" world, many use the term "AN" to designate a JIC fitting, and for their purpose there is no harm. However, in the aerospace world we do not consider JIC as a suitable product to use on type certified aircraft. In fact, as the link explains, there has been arrests made by the Justice Department for selling JIC fittings into the aerospace market as "AN" fittings.