The number of an AN fitting is the fitting size not the nut size. Each # is 1/16 of an inch. For example a #4 fitting is for 1/4 in tube, #8 is 1/2 in etc. The wrench size for the nut on a #4 fitting is 9/16 wrench size. I worked in the aerospace industry for 27 years and never ran into any metric AN fittings.
I worked on a lot of stuff that used different AN fittings in the .mil and they are excellent, but I sure don't see the point in using counterfeit shit just to look good. "It's your build" as the saying goes but buy the genuine article. I bet the reason those fittings hecame a thing in hot rods is probably because they ended up coming home in guys lunch boxes from Long Beach. But I wouldn't trust the el-cheapos, the whole point is to have something better, not worse, than OEM.
Yes !! I am One that knows that / this !!! most simple people that do not work in the Aerospace where you more likely have a $500 Special specific each size made wrench for installing a fitting or nut , In the race car world we have a aluminum wrenches that are marked The Common sizes 3 threw 20 as a quick reference, like 1/4 inch = 0.2500 thousands =1/4 Or 1/8 =0.125 0 x 2 = 1/4 inch witch is 0.2500 thousands = 1/4 or we can brake it down even more 16s 32s . & You being in Aerospace You can probably break it down even further. My statement was the cheap China made sold on evil bay , knock off A&N fittings they are a metric size So Your standard Aluminum wrenches that are marked lets say a #6 will not fit Correctly on cheap knock off A&N fittings ,,, I've been around people maybe helping them at their shop or racecar trailer and I say I need a 9/16 wrench they would tell me ""I don't have a 9/16 "" but I have a 15 mm wrench/socket it's the same and I'm like ""No it's not!!! "" Yes you can put a 15 mm wrench/socket on a 9/16 bolt head or nut but you cannot put a 9/16 wrench or socket on a 15 mm head bolt or nut. Now this also depends if it's a 6 point or 12 point nut or bolt head, In my toolboxes I also have specialty Aviation tools and splined sockets and wrenches.
Some French aircraft have what look to be AN fittings; but are designed around metric hose and tubing sizes... was a pain in the neck to adapt this to use inch AN fittings.
AN does not mean that a fitting has certain thread characteristics or sizing (even though it does), it means it meets requirements as laid down by the Army and the Navy (AN) to meet or exceed reliabilty needs. If it is sold as an AN spec part, its supposed to meet those standards no matter who manufactures it or who buys it. Anything manufactured and advertised as an AN capable product that fails easily should be reported as fraudulent. I know there are copies of some products like fuel pressure regulators that come with fittings and the quality isn't there. Then there are JIC fittings which do not meet AN standards (they don't certify them as AN quality) but are very strong and rugged and reliable. They are usually/always (?) made of steel and are used on virtually everything used industrially. They are a lot cheaper and you can get quanity instead of single buys. They look good too, they just aren't anodized blue/red/black. I don't think AN has a #5 (5/16) but JIC does. Look up a company on line called Discount Hydraulics. They have some nice wall charts too. https://www.discounthydraulichose.com/
I've use local supplier, Speedflow as well as Parker. So far far so good. Use soft jaw wrenches to prevent marring finish.
Phenix brand fittings and hose. USA made. ( idaho and California) Great people Great service Great quality.. Dave
Russell.....Earls......pretty much all the "name" brand stuff is good for most applications. The universal thing about all of em' is they're expensive. I got a box with every last one of them that I replaced or didn't use, just for that reason.
Parker, Everflex and Aeroquip are major suppliers they actually extruded the PTFE tubing and braid the SS reinforcement. My choice for Fuel lines are "conductive" PTFE with the innermost tube having Carbon black inner core to eliminate static discharge ask for it, Parker can supply it .
I use AN fittings as much as possible. Brake lines are all 3/16-inch stainless AN. I've had good luck with the kit from Speedway Motors plus a few odd fittings not included. Fuel systems are the same, depending on the requirements (AN-6 vs AN-8, etc). Holley, Earls, Russell, Aeromotive all produce reliable products. Any fuel line underneath the car gets the AN treatment as opposed to the standard hose and clamp, especially customer cars. Ya think they're ever gonna crawl under the car and check those clamps?! Using AN fittings almost guarantees a leak free joint for years to comes. There's a reason it's "industry standard" in the aviation world, as previously mentioned. Get a good hose/fitting installation tool like what Koul Tools sells, a decent bender, and a good flaring tool like the turret one from Eastwood or the handheld style from Ridgid and the plumbing world is your Oyster!
I've been building and working on race cars for 30 years, probably built 100 miles of stainless braided line, -3 to -20. At all the shops I've worked at they have boxes of used hose ends, not often you get a new end. In all that time I've only had a couple of fittings leak and their usually old and worn out or cracked from a crash. We don't know the brands, you take the newest looking ones that are the same color. If by chance I've come across a situation where I need a new hose end I go with XRP.
Back in the day, people used to get a lot of stuff including AN fittings and hose from surplus stores. Are there still military surplus stores or is that a relic from the past?
I use AN fittings as much as I can. It's a hell of a lot easier to do a 37* than a 45* double flaring.
Words of wisdom! You just have to remember to put two things on the tube before you flare, not just one. Now, if NiCu tubing only came in more sizes to make bending easier. I have a full flow filter mod project for a flathead Dodge that would be much easier.
I was wondering when someone would mention Red Horse. I have used them on a few cars and they work good, look good and priced good. Clear finish for me but I do dig the black fittings on page 1.
I used a brand I won’t mention. I think they make them in house. Seemed like good stuff until the anodizing started fading on some of them. Black fittings on my carbs are now grey. I won’t use them again.
I bought all my AN-6 hose with swaged brass fittings from McMaster Carr. I believe it's Parker, but can't recall at the moment. I plumbed my car with it over twenty years ago, really nice stuff.
@19Eddy30: Just for info, does anyone remember 1950s open end/combination wrench sets from 'way back? There was a peculiar size wrench, just between 9/16" and 5/8". It was 19/32". Synonymously, 15mm. Just a 'little known fact'...