AN-4 conversion
TECH Fanatic
Joined: Sep 2004
Posts: 1,124
Likes: 1
From: Las Vegas
-4 AN is 7/16x20 UNF/JIC; 1/4x19 BSP; 1/4x18 NPT
Basically, its 1/4" line size.
Goto Section 10, page 95
Basically, its 1/4" line size.
Goto Section 10, page 95
Just FYI, AN sizes are the numerator in a fraction where the denominator is 16ths of an inch. So, -4 is (4/16 or 1/4"), -8 is (8/16 or 1/2"), -6 is (6/16 or 3/8"), etc. Apparently the Army and Navy (hence AN) decided that fractions were a bit too complicated and decided not to use the metric system way back when they came up with the AN designations.
on the topic of thread conversions, i have a quick question.
i was looking for a fitting for my power steering gearbox while at the hydraulic shop this past weekend.
I gave the guy a fitting that screwed in correctly and asked him the threads, was it AN, NPT, JIC or something else...he said "Oh, that's 3/8" in 'US Thread' inverted flare".
Does anyone know how 3/8 "US Thread" translates to AN or NPT and other sizes? Apparently it's used with fuel lines and other things they had laying around in the hydraulic shop.
i was looking for a fitting for my power steering gearbox while at the hydraulic shop this past weekend.
I gave the guy a fitting that screwed in correctly and asked him the threads, was it AN, NPT, JIC or something else...he said "Oh, that's 3/8" in 'US Thread' inverted flare".
Does anyone know how 3/8 "US Thread" translates to AN or NPT and other sizes? Apparently it's used with fuel lines and other things they had laying around in the hydraulic shop.
TECH Regular
Joined: Jan 2004
Posts: 426
Likes: 4
From: Austin, TX
3/8" inverted flare uses a 45 degree flare, while AN, or more corectly, JIC, uses a 37 degree flare. They are not interchangeable.
The inverted flare is also known as an SAE flare, and was used on all OEM automotive applications until newer bubble flare, metric flare, and oring type fittings came into use a few years ago. SAE flares are still used exclusively on braking systems on all OEM applications.
The AN or JIC was used in aircraft. That is where the term AN name into use, it stands for Army/Navy standard.
NPT stands for National Pipe Thread. It is a tapered thread that seals by an interference fit between it's threads, unlike flare fittings that seal a flare over an inverted cone. NPT fittings are used on plumbing pipes in your house, and about the only place that they have been used on cars for a long time, is for the heater hose fittings where they go into the waterpump or intake manifold.
A lot of guys use AN fittings because they can be single flared, while the SAE flares have to be double flared. Double flaring stainless tubing can be a real challenge if you do not have a hydraulic flaring tool. The real nightmare, and the real costs, come with finding all the proper fittings to adapt from whatever fitting is already existing, to the AN fitting. AN fittings also look Cool and all the braided hose systems on the market today are based on the AN fittings.
Regards, John McGraw
The inverted flare is also known as an SAE flare, and was used on all OEM automotive applications until newer bubble flare, metric flare, and oring type fittings came into use a few years ago. SAE flares are still used exclusively on braking systems on all OEM applications.
The AN or JIC was used in aircraft. That is where the term AN name into use, it stands for Army/Navy standard.
NPT stands for National Pipe Thread. It is a tapered thread that seals by an interference fit between it's threads, unlike flare fittings that seal a flare over an inverted cone. NPT fittings are used on plumbing pipes in your house, and about the only place that they have been used on cars for a long time, is for the heater hose fittings where they go into the waterpump or intake manifold.
A lot of guys use AN fittings because they can be single flared, while the SAE flares have to be double flared. Double flaring stainless tubing can be a real challenge if you do not have a hydraulic flaring tool. The real nightmare, and the real costs, come with finding all the proper fittings to adapt from whatever fitting is already existing, to the AN fitting. AN fittings also look Cool and all the braided hose systems on the market today are based on the AN fittings.
Regards, John McGraw
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