JIC Fittings Guide › JIC vs AN

JIC vs AN Fittings: Interchangeability Explained

JIC and AN fittings are the most commonly confused pair in hydraulics. They share the same 37° flare angle and the same thread size at each dash number, so they assemble and seal together. But they are built to different specifications for different industries. This guide explains what is the same, what is different, and when substitution is acceptable. For JIC dimensions, see the main JIC fittings guide.

Background

AN stands for Army-Navy (also described as Air Force–Navy Aeronautical Design Standard). The 37° flare system was originally developed for U.S. military aviation. According to fitting maker Air-Way Manufacturing, as 37° fittings spread into industrial markets in the 1960s, many variants claiming AN compliance appeared, and the Joint Industry Council created the JIC standard: a 37° fitting with a slightly lower class of thread than the military version. SAE later adopted it, and today industrial 37° fittings are specified by SAE J514 and ISO 8434-2.

What Is the Same

• Flare angle: both seal on a 37° cone.
• Thread size and pitch: at a given dash number the threads match — for example AN-6 and -6 JIC are both 9/16-18, and AN-8 and -8 JIC are both 3/4-16.
• Dash sizing: the dash number is the tube OD in sixteenths of an inch for both.

Because of this, an AN male will thread onto and seal against a JIC female of the same dash size, and vice versa. You cannot tell them apart with calipers or a pitch gauge.

What Is Different

Thread class and root radius

Unified inch threads come in fit classes 1, 2 and 3 (A for male, B for female); higher numbers mean tighter tolerances. SAE J514 fittings use Class 2A/2B, the balance of performance and economy used in nearly all commercial threads. AN fittings use Class 3A/3B with a J-form thread, which has an enlarged root radius to reduce stress concentration. Air-Way credits the J-thread and Class 3 tolerance with about 40% higher fatigue strength and 10% higher shear strength.

Specifications

The Defense Logistics Agency lists MIL-F-5509 as canceled, and Fluid Power Journal notes AN flare fittings are covered by the SAE aerospace standard AS4841. If a drawing or maintenance manual calls for an AN, MS or AS part number, that is the requirement — not a generic 37° fitting.

When Can You Substitute?

Usually acceptable

• Using JIC fittings in industrial, agricultural, construction or material-handling hydraulics, even where someone has loosely called them "AN".
• Using AN fittings in an industrial system — they will work, but you are paying for tolerances you do not need.
• Motorsport and automotive aftermarket plumbing marketed as "AN" is frequently built to JIC-equivalent dimensions; follow the component maker's guidance and your sanctioning body's rules.

Not acceptable

• Installing JIC fittings in aircraft, aerospace or military assemblies that specify AN, MS or AS parts. Air-Way states plainly that JIC fittings are not acceptable for military aviation or aerospace use.
• Any safety-critical application where the documentation specifies an aerospace part number, unless engineering approves the change.

Telling Them Apart

Since the dimensions match, identification relies on markings and finish:

• Look for stamped AN, MS or AS part numbers.
• Aluminum AN fittings are typically anodized, often in color codes.
• Check the packaging, certification and traceability paperwork; aerospace parts come with material certs.
• Industrial JIC fittings are usually zinc-plated carbon steel or plain 316 stainless.

To confirm a fitting is a 37° flare at all (and not 45° SAE or ORFS), follow our step-by-step identification guide.

Thread Sizes (Same for JIC and AN)

-2 5/16-24, -3 3/8-24, -4 7/16-20, -5 1/2-20, -6 9/16-18, -8 3/4-16, -10 7/8-14, -12 1-1/16-12, -14 1-3/16-12, -16 1-5/16-12, -20 1-5/8-12, -24 1-7/8-12, -32 2-1/2-12. Full dimensions including male OD and female ID are in our JIC thread size chart.

Ordering Advice

For industrial hydraulics, request SAE J514 / JIC 37° fittings — you get the same function at lower cost and much broader availability. For aerospace, order to the specified part number from an approved source. See also JIC vs NPT and JIC vs ORFS.

Why the Confusion Persists

The term "AN" is widely used as shorthand for any 37° flare fitting sized in dash numbers, particularly in motorsport and performance automotive circles. Aftermarket catalogs label hose ends and adapters "AN-6" or "-6 AN" even when the parts are not made or certified to aerospace specifications. That is not necessarily a problem for a race car fuel line, but it does mean a part labeled "AN" on a retail site is not automatically an aerospace-qualified part. Conversely, industrial buyers sometimes request "AN fittings" when what they really need is standard SAE J514 JIC hardware at industrial prices.

When writing a purchase request, be explicit. For industrial work, ask for "SAE J514 37° flare (JIC)". For aerospace, quote the exact AN, MS or AS part number from the drawing or manual and require certification. This avoids both overpaying and under-specifying.

Mixing AN and JIC in One System

In industrial systems, mating an AN male with a JIC female (or the reverse) of the same dash size is common and generally works, since the flare geometry and threads match. Watch for galvanic issues when mixing aluminum AN fittings with steel JIC parts in wet or corrosive environments, and respect the lower pressure capability typical of aluminum fittings compared with steel. When in doubt, check the pressure rating published by each manufacturer for the specific part.

FAQ

Related guides

• JIC Fittings Guide (main)
• JIC vs NPT
• JIC vs ORFS
• How to Identify a JIC Fitting
• JIC Thread Size Chart
• -4 JIC Fittings
• -6 JIC Fittings
• -8 JIC Fittings
• -10 JIC Fittings
• -12 JIC Fittings
• -16 JIC Fittings
• JIC vs SAE 45° Flare
• JIC vs BSPP
• JIC vs Metric (DIN 24°)
• JIC Torque Specs
• JIC Fitting Types
• JIC Materials & Pressure Ratings

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