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SAE J514 · ISO 8434-2

JIC 37 degree flare (SAE J514 / ISO 8434-2)

A straight Unified inch thread with a 37 degree metal cone seat. The most common hydraulic connection on North American equipment.

13 sizes60 degree flanksParallel thread37 degree flare cone

Identify a fittingCompare with a lookalike
37 degree flare cone, on a parallel thread3737 degree coneParallel threadOpen end on the left
Schematic cross-section of the male half, upper side only, with the centre line dashed and the open end on the left. Cone angles are drawn at their true angle from the axis; nothing else is to scale and no dimension should be measured off it.

How to recognise it

A male nose machined to a shallow cone, or a female fitting with a coned recess. Measured off the fitting axis the cone half-angle is 37 degrees, so the included angle across the cone is 74 degrees.

Where it seals: Metal to metal, cone against the flared tube or the mating cone. No O-ring, no sealant.

Mating two different cone angles is the classic way to make a joint that holds pressure on the bench and weeps in service: the two cones touch on a line instead of a face, and tightening harder cold-flows the softer of the two rather than sealing it.

How it is sized

Sized by dash number, which is the tube outside diameter in sixteenths of an inch: -08 is 8/16 in, half-inch tube.

Where you will find it: General hydraulics, agricultural and construction equipment, hose adapters, anywhere a re-usable metal-to-metal joint is wanted.

Also searched as: JIC, 37 degree flare, AN fitting, SAE 37.

All sizes

JIC 37 degree flare size table

Thread, pitch, diameters and working pressure for every JIC 37 degree flare size in the database.
SizeThreadTPI / pitchBasic major ØMeasured across crestsTube / trade sizeWorking pressure
-02 JIC5/16-24 UNF24 TPI (1.058 mm pitch)7.94 mm / 0.313 inNot published0.125 in5,000 psi (345 bar)
-03 JIC3/8-24 UNF24 TPI (1.058 mm pitch)9.53 mm / 0.375 in9.5 mm to 9.65 mm0.1875 in5,000 psi (345 bar)
-04 JIC7/16-20 UNF20 TPI (1.27 mm pitch)11.11 mm / 0.438 in11 mm to 11.18 mm0.25 in5,000 psi (345 bar)
-05 JIC1/2-20 UNF20 TPI (1.27 mm pitch)12.7 mm / 0.5 in12.5 mm to 12.7 mm0.3125 in5,000 psi (345 bar)
-06 JIC9/16-18 UNF18 TPI (1.411 mm pitch)14.29 mm / 0.563 in14.1 mm to 14.3 mm0.375 in5,000 psi (345 bar)
-08 JIC3/4-16 UNF16 TPI (1.587 mm pitch)19.05 mm / 0.75 in18.9 mm to 19.1 mm0.5 in4,500 psi (310 bar)
-10 JIC7/8-14 UNF14 TPI (1.814 mm pitch)22.23 mm / 0.875 in22.1 mm to 22.35 mm0.625 in3,500 psi (241 bar)
-12 JIC1 1/16-12 UN12 TPI (2.117 mm pitch)26.99 mm / 1.063 in26.9 mm to 27 mm0.75 in3,500 psi (241 bar)
-14 JIC1 3/16-12 UN12 TPI (2.117 mm pitch)30.16 mm / 1.188 in30 mm to 30.23 mm0.875 in3,000 psi (207 bar)
-16 JIC1 5/16-12 UN12 TPI (2.117 mm pitch)33.34 mm / 1.313 in33.2 mm to 33.3 mm1 in3,000 psi (207 bar)
-20 JIC1 5/8-12 UN12 TPI (2.117 mm pitch)41.27 mm / 1.625 in41.2 mm to 41.4 mm1.25 in2,500 psi (172 bar)
-24 JIC1 7/8-12 UN12 TPI (2.117 mm pitch)47.62 mm / 1.875 in47.6 mm to 47.75 mm1.5 in2,000 psi (138 bar)
-32 JIC2 1/2-12 UN12 TPI (2.117 mm pitch)63.5 mm / 2.5 in63.3 mm to 63.5 mm2 in1,500 psi (103 bar)

13 of the 13 sizes carry a published working pressure. Every one of them prints the exact conditions it applies under on its own page - a figure without its material and safety factor is not a rating.

On paper

Identification sheets covering JIC 37 degree flare

SAE inch fittings: JIC 37, ORB, ORFS and SAE 454 sectionsSeat and thread identification: all ten standards1 sectionsPublished working pressures, with the conditions they apply under5 sections

Where these figures come from

Dimensions are as defined by SAE J514, ISO 8434-2. FittingKey is an independent reference and is not affiliated with, endorsed by or approved by any standards body or fitting manufacturer.

Every value on this page was checked against 7 independent published sources:

Which published source supplied each column, and what it gave.
ColumnSourcesWhat they gave
Dash and trade sizetompkins, mcgill-id, chs-orfs, gageref-jicFour publishers give the same dash-to-tube-size map. Three of them carry the -14 row; one omits it.
Thread designation and pitchtompkins, mcgill-id, chs-orfs, gageref-jicAll four give the same thread for every dash size, including the 12 TPI constant-pitch series from -12 upward.
Basic major diametertompkins, mcgill-idThe thread designation fixes the basic major diameter: a 3/4-16 UNF thread has a basic major diameter of 0.750 in, which is 19.05 mm at 1 in = 25.4 mm exactly. The inch and millimetre columns are that one figure in two units.
Measured male thread diametergates-idchart, apex-threadid, mcgill-idThree identification charts. Their figures sit within 0.25 mm of one another, and the span of all three is what the size page publishes.
Working pressuretompkins, brennan-pressureTwo manufacturer catalogues, both stating a steel fitting at a 4 to 1 design factor against minimum burst per SAE J514. They agree on all thirteen sizes to the psi.