The Stovebolt Site Forums The Shop Area General Truck Talk Question On Fittings ???

Ok stupid question time. I understand Double Flares, I know NPT is National Pipe Thread , But what the heck is an "AN" fitting? I have been looking at fuel filters and some are listed with 8AN, 10AN, 12AN fittings. A little Help please. What do they fit Is it going to be a metric size?

"Army Navy" is a type of fitting designed for connecting flex line [like rubber] fittings to rigid metal tube fittings

Bill

An "AN" fitting is just a standard fitting that has a single flare at 37 degrees. You can get the flare on one side and about anything on the other, such as NPT or straight thread. The number is the size divided by 16, like "6AN" would be 6/16 or 3/8. "8AN" would be 8/16 or 1/2. This is in tubing size, which is measured in the ID (inside diameter). There are many manufacturers of this type of fittings. All of the HiPO dealers sells them (Jegs, Summit, Herberts).
Hope this helps
Steve

Wow thanks for the info. I knew I could get the answer here. So only with an adapter is it compatible with double flare fittings?

I ran AN fitting for my fuel lines and tramsmission cooler lines. It gets a little complicated ie. braided SS or SS tubing each have different fittings. If you're making your own lines study all you can find on the internet or give me a shout out. I had a difficult time getting a adapter from my wheel cylinder to AN SS braided. the difficult thing was to get a correct angled adapter on the Chev. wheel cylinder to clear the axle housing. Give me PM and I'll help walk you through it. PS. Alway match manufaturer's fittings to same manufacturer's SS braided and tubing. Dia.s do differ between manufacturers

.

thx fo the info. i'll start studyin'

Yes and no... 37* flared tube ends can also be double flared, I have two different tool sets (one brand new) that will double flare 37*

The more common double flared tube like for brake and fuel lines on our (original) trucks use a 45* angle.

To go from a 37* flare to a 45* flare fitting or tube you need an adapter of some sort, or reflare the tube to the type you need.

Also note that AN fittings are for our purposes the exact same as JIC (Joint Industrial Council) fittings, which are (as expected) also 37* flare. These are normal and extremely common hydraulic fittings and any shop that makes hoses or works on heavy equipment will have an assortment of JIC fittings and adapters.
Good to know if you think you're stuck looking for an "AN" fitting on short notice you can likely find one in town instead of ordering from a catalog. Main difference is JIC stuff is usually steel and AN stuff is usually aluminum, and they are interchangeable.

Grigg

I don't think I will be going down this road. I just keep seeing the AN fittings everywhere I look and wondered how they fit into the general scheme of things. It seems some of the AN fittings are more popular for fuel delivery than the double flare stuff so I wondered how compatable it was, but I am really not into mix and match fittings, adapters and then more fittings.I appreciate all the info you guys have been very helpfull. I'm sure there will be more questions to come.

I disagree with the statement that the AN size is inside diameter of the tubing, it's outside diameter. There are all different sizes of tubing wall thicknesses but you use the same size nut for all of them in a size range. It's been awhile but common thicknesses are .032 .049 .062 and in bigger tubing .125 for really high pressure. I hope that made sense, for example,1/2 inch tubing will measure 1/2 inch outside diameter no matter what wall thickness you get, the inside diameter varies. The aircraft industry uses lots of AN fittings in aluminum, I used lots in the oil industry in stainless. Dave

Correct, tube size is the Outside Diameter for all the fitting designs discussed so far..

Yes you are right it is the outside diameter. I miss stated that. Brain failure. Sorry about that.
Steve

I agree with the last two posts. I sold Weatherhead and Gates fittings for years and tubing size was always O.D.