JIC 37 degree flare (SAE J514)
The industrial 37 degree flare. Carbon steel, stainless or brass, to SAE J514 and ISO 8434-2.
60 degree flanksParallel37 degree flare cone
Confusion pair
JIC vs AN fittings
The same 37 degree flare and the same thread at every dash size. AN is the tighter aerospace specification of the same joint, not a different connection.
AN 37 degree flare (MIL-F-5509 and the AN / MS part series)
The military and aerospace 37 degree flare. Stainless, aluminium or brass, held to a tighter thread class, and normally anodised in the colour-coded finishes the aviation trade expects.
Not a separate connection in this database. It is the same joint as the family on the left, held to a different specification, so it has no dimensions of its own.
The three answers
What actually happens if you put them together
What interchanges
- The flare angle is the same 37 degrees on both, and at matching dash sizes the thread is the same too: an AN-6 and a -06 JIC are both 9/16-18. Both sources describe them as dimensionally the same joint.
- For industrial and general hydraulic work the two are described by both publishers as interchangeable, and an AN male will seal against a JIC female of the same dash and the reverse.
What threads together and will still leak or fail
This is a safety statement, so it is only made where it is sourced. Each item below either cites a published statement that the two are not interchangeable, or rests on the figures on the size pages showing an identical thread with a different seat.
- A JIC fitting in a military aviation or aerospace assembly. It will thread on and seal, and it is still the wrong part: one publisher states plainly that JIC fittings are not acceptable for military aviation or aerospace use, because AN carries an increased root radius J thread and a Class 3 tolerance that the industrial part does not, and which the publisher credits with a 40 per cent higher fatigue strength and 10 per cent higher shear strength. Substituting on the bench is undetectable and shows up as a fatigue failure later.
What will not fit at all
- Nothing. There is no size at which an AN and a JIC of the same dash will refuse to assemble, which is precisely what makes the substitution above easy to make by accident.
The check that settles it
You cannot separate them with a caliper or a pitch gauge - the dimensions are the same. Read the part marking and the finish. AN and MS part numbers are stamped on the fitting, and aerospace AN parts are normally anodised to a colour code, where the industrial part is plain steel or plated.
Size by size
Where the threads match, and where they do not
13 of the 13 sizes below run the same thread count within half a millimetre on diameter. Those are the rows that will screw together. Built from the published dimensions at page-build time, not from a hand-kept list.
| Size | JIC 37 degree flare | AN 37 degree flare | Will they assemble? |
|---|---|---|---|
| -02 | 5/16-24 UNF · 7.94 mm | AN-02 · 5/16-24 UNF | Yes, and it will seal - the joint is the same |
| -03 | 3/8-24 UNF · 9.53 mm | AN-03 · 3/8-24 UNF | Yes, and it will seal - the joint is the same |
| -04 | 7/16-20 UNF · 11.11 mm | AN-04 · 7/16-20 UNF | Yes, and it will seal - the joint is the same |
| -05 | 1/2-20 UNF · 12.7 mm | AN-05 · 1/2-20 UNF | Yes, and it will seal - the joint is the same |
| -06 | 9/16-18 UNF · 14.29 mm | AN-06 · 9/16-18 UNF | Yes, and it will seal - the joint is the same |
| -08 | 3/4-16 UNF · 19.05 mm | AN-08 · 3/4-16 UNF | Yes, and it will seal - the joint is the same |
| -10 | 7/8-14 UNF · 22.23 mm | AN-10 · 7/8-14 UNF | Yes, and it will seal - the joint is the same |
| -12 | 1 1/16-12 UN · 26.99 mm | AN-12 · 1 1/16-12 UN | Yes, and it will seal - the joint is the same |
| -14 | 1 3/16-12 UN · 30.16 mm | AN-14 · 1 3/16-12 UN | Yes, and it will seal - the joint is the same |
| -16 | 1 5/16-12 UN · 33.34 mm | AN-16 · 1 5/16-12 UN | Yes, and it will seal - the joint is the same |
| -20 | 1 5/8-12 UN · 41.27 mm | AN-20 · 1 5/8-12 UN | Yes, and it will seal - the joint is the same |
| -24 | 1 7/8-12 UN · 47.62 mm | AN-24 · 1 7/8-12 UN | Yes, and it will seal - the joint is the same |
| -32 | 2 1/2-12 UN · 63.5 mm | AN-32 · 2 1/2-12 UN | Yes, and it will seal - the joint is the same |
Detail
Everything each family carries
| Property | JIC 37 degree flare | AN 37 degree flare |
|---|---|---|
| Flank angle | 60 degrees | 60 degrees (same joint, different specification) |
| Parallel or tapered | Parallel | Parallel (same joint, different specification) |
| Seat | 37 degree flare cone | 37 degree flare cone (same joint, different specification) |
| Where it seals | Metal to metal, cone against the flared tube or the mating cone. No O-ring, no sealant. | Metal to metal, cone against the flared tube or the mating cone. No O-ring, no sealant. (same joint, different specification) |
| Defined by | SAE J514, ISO 8434-2 | SAE J514, ISO 8434-2 (same joint, different specification) |
| Sized by | Sized by dash number, which is the tube outside diameter in sixteenths of an inch: -08 is 8/16 in, half-inch tube. | Sized by dash number, which is the tube outside diameter in sixteenths of an inch: -08 is 8/16 in, half-inch tube. (same joint, different specification) |
Answers
Common questions
Will a JIC 37 degree flare screw into a AN 37 degree flare?
A JIC fitting in a military aviation or aerospace assembly. It will thread on and seal, and it is still the wrong part: one publisher states plainly that JIC fittings are not acceptable for military aviation or aerospace use, because AN carries an increased root radius J thread and a Class 3 tolerance that the industrial part does not, and which the publisher credits with a 40 per cent higher fatigue strength and 10 per cent higher shear strength. Substituting on the bench is undetectable and shows up as a fatigue failure later.
Are JIC and AN interchangeable?
The flare angle is the same 37 degrees on both, and at matching dash sizes the thread is the same too: an AN-6 and a -06 JIC are both 9/16-18. Both sources describe them as dimensionally the same joint.
How do I tell them apart?
You cannot separate them with a caliper or a pitch gauge - the dimensions are the same. Read the part marking and the finish. AN and MS part numbers are stamped on the fitting, and aerospace AN parts are normally anodised to a colour code, where the industrial part is plain steel or plated.
More pairs
Other fittings people mix up
Where these figures come from
Every value on this page was checked against 4 independent published sources:
- Fluid Ports and Connectors Identification Guide - McGill Hose & Coupling, SAE J512, J514, J1453, J1926-1, ISO 228, ISO 7, DIN 2353, JIS (distributor, read 2026-08-27)
- Master catalogue: conformance, working pressure and torque tables - Tompkins Industries, SAE J514, SAE J1453, SAE J1926-1, SAE J1926-3, ISO 11926-1 (manufacturer, read 2026-08-27)
- The differences between AN and JIC 37 degree flare fittings - Motion & Flow Control Products, SAE J514, ISO 8434-2 (distributor, read 2026-08-27)
- What is the difference between AN and JIC fittings - Air-Way Manufacturing, MIL-F-5509, SAE J514, ISO 8434-2 (manufacturer, read 2026-08-27)