JIC vs DIN 2353: 37° Flare vs 24° Bite-Type Fittings Compared

JIC seals on a 37° metal flare formed at the end of the tube, sized per SAE J514 in inch dash sizes. DIN 2353 works differently: a 24° cutting ring bites into the tube's outside diameter, per ISO 8434-1, in metric tube-OD, light and heavy series. Seat angle differs. Thread differs. Sizing system differs. Swap one for the other without an adapter and nothing lines up, so specify the wrong standard and you're left with a joint that simply won't seal.

On this page, "JIC" refers to the SAE J514 37° flared tube fitting used in hydraulics and instrumentation. It isn't the aerospace AN fitting, even though the two share the 37° cone. "Bite-type" or "compression," meanwhile, means the DIN 2353 24° cutting-ring connector, not a copper-plumbing compression fitting.

JIC vs DIN 2353 at a Glance: 37° Flare vs 24° Bite-Type Comparison

Want to see how a 37° JIC flare connection stacks up against a DIN 2353 24° bite-type connection? The table below lays it out fast, covering sealing, thread, sizing, and pressure side by side. Figures not attributed to Crestflo are standard published values pulled straight from the governing standards. They follow the applicable standard, and they can be customized to requirement.

What Is a JIC (37° Flare) Fitting?

A JIC fitting is a flared tube connector, and its seal comes from a 37° cone: the tube end gets flared out to 37° and clamped, metal-to-metal, against a matching 37° seat in the fitting body, with a threaded nut supplying the clamping force. SAE J514 governs the design, and its metric-thread cousin is ISO 8434-2. "JIC" stands for Joint Industry Council, the body that first standardized it. The seal sits on the flare, not the thread, so the thread itself is a straight UN/UNF inch thread whose only job is to draw the joint together. Sizing runs by inch dash number. A -8 fitting, for instance, takes 1/2″ tube and carries a 3/4-16 thread.

The 37° flare shares its cone angle with the aerospace AN fitting. AN parts, though, are held to tighter thread-class and inspection tolerances, so don't treat the two as freely interchangeable. JIC is a mainstay of North American hydraulics and fluid power, and it turns up often on instrumentation where engineers want a reusable, tool-formed metal seal.

Crestflo manufactures 37° flare fittings to ISO 8434-2, with PED compliance where required, see 37° JIC flare fittings and JIC-37 tube fittings.

What Is a DIN 2353 (24° Bite-Type) Fitting?

A DIN 2353 fitting is a bite-type, or cutting-ring, tube connector. Its seal comes from a hardened ring that bites into the tube's outside diameter as a nut is tightened over a 24° cone. DIN is the German standards body, Deutsches Institut für Normung. DIN 2353 covers the 24° cone tube connection used throughout European hydraulic equipment, and it's harmonized internationally as ISO 8434-1. The cutting ring itself is detailed in DIN 3861/3865, and stud ends fall under DIN 3852. No flaring is needed here: the tube gets cut square, inserted, and the ring is set through controlled nut torque, which forms both the mechanical grip and the seal in a single action.

These connectors are sized by metric tube OD across two pressure classes. There's L (light, or leicht) for lower pressure and thinner-wall tube, and S (heavy, or schwer) for higher pressure and thicker wall. Progressive-ring and functional-cutting-ring variants exist too, and they improve grip and repeatability.

Some in the industry still call this family by its Parker Ermeto EO and EO-2 trade names. EO and Ermeto are trademarks of Parker Hannifin Corporation. Crestflo carries DIN 2353 bite-type fittings across its full alloy range; see DIN 2353 tube fittings.

Sealing Geometry: 37° Flare vs 24° Cutting Ring

These two standards solve the same problem, sealing a tube to a port, but they take opposite approaches. That's the core of the flare vs compression fitting comparison. A JIC joint reshapes the tube itself. Flaring tooling forms a 37° cone on the tube end, and that flare sits sandwiched metal-to-metal between the fitting nose and nut. Seal quality hinges on a clean, correctly angled flare, plus torque that isn't too low (it'll leak) or too high (it'll crack the flare). A DIN 2353 joint takes a different path: it deforms a separate ring instead of the tube. As the union nut advances over the 24° cone, the ring's edge cuts into the tube OD while its body wedges against the cone, producing a grip-and-seal without touching the tube's original geometry beyond that bite. Both are all-metal seals built for high pressure and a wide temperature range. Yet the flare depends on tube preparation, while the cutting ring depends on ring geometry and set torque. For a look at how compression ferrules seal by comparison, see single vs double vs ferrule-less ferrules.

JIC and DIN 2353 Threads & Sizing: Inch Dash vs Metric OD

Thread type and sizing are where JIC and DIN 2353 pull apart most for anyone placing an order. JIC runs a straight UN/UNF inch thread and gets specified by dash size: each dash equals 1/16″ of nominal tube OD, so a -8 fitting takes 1/2″ tube. The thread itself only clamps the joint together; the flare does the actual sealing. DIN 2353, by contrast, puts a straight metric thread on the union nut and gets ordered by metric tube OD (6, 8, 10, 12 mm and up) within the L or S series, with stud ends cut to DIN 3852. One system counts in inches, the other in millimeters, so a JIC nut and a DIN 2353 nut that look about the same size won't share a thread and won't mate. Check the system before you order, using Crestflo's thread identification guide; for the broader metric-versus-inch call, see Crestflo's metric vs imperial tube fittings page.

JIC vs DIN 2353 Pressure Ratings: Dash Sizes vs L and S Series

Size works against both families: bigger tube, lower pressure. Each publishes its ratings against the standard that governs it, not one headline number. For JIC, pressure falls as the dash size climbs, and the smallest dash sizes carry the highest ratings; maxima run to roughly 5,000+ psi, depending on size, tube, and material. DIN 2353 handles it differently, splitting the rating by series: the L (light) series tops out near 315 bar (~4,500 psi), and the S (heavy) series reaches about 630 bar (~9,000 psi). Again, the small sizes hold the highest numbers. Crestflo's own 37° flare fittings are built to ISO 8434-2, rated for working pressure up to 15,000 psi, sizes up to 2″ (50 mm) OD, and temperatures up to 350°C. They're NACE-compliant as well. DIN 2353 bite-type fittings, by contrast, get their ratings by L/S series. Every figure follows its applicable standard and can be adjusted to what the job calls for. See pressure, temperature derating for how these ratings shift with temperature.

JIC 37° Flare Dimensions: Dash Size, Tube OD & Thread Chart

The JIC dash-size chart below lists standard SAE J514 tube ODs and straight-thread sizes. These figures aren't invented; they're published standard values, pulled directly from the applicable standard. Even so, sizes can be adjusted to fit your specific requirement.

DIN 2353 Dimensions: Metric Tube OD, Series & Union-Nut Thread

The chart below, drawn from DIN 2353, sets out standard tube ODs, series, and union-nut metric threads per ISO 8434-1. These figures are the standard published ones, and they can be adjusted to fit whatever the job calls for.

Standards Cross-Reference: SAE J514, ISO 8434-1, ISO 8434-2 & DIN 3861/3865

Both families fall within a tight cluster of standards. This reference lines up each one with what it actually governs.

How to Tell a JIC Fitting from a DIN 2353 Fitting

Crestflo's fittings guide: JIC vs. DIN 2353, identified in the field.

You can usually tell the two apart with a gauge and a quick pitch check. Start with the seat angle: a 37° flared seat means JIC, while a 24° cone with a ring inside the nut points to DIN 2353. Next comes the thread. JIC uses an inch UN/UNF thread; DIN 2353 uses metric. A thread pitch gauge will settle that in seconds. Then look at the tube end itself, a JIC tube is visibly flared, whereas a DIN 2353 tube is cut square, with a captive ring gripping the OD just behind the nut. Don't guess from nominal size when you're unsure. Measure the thread and the cone instead. For the full method, pitch gauges, calipers, and all, see the thread identification guide.

Do JIC and DIN 2353 Interchange? Adapters & Equivalents

JIC and DIN 2353 don't interchange directly. The 37° flare and the 24° cone are different seats, cut on different threads, in different sizing systems entirely, so a JIC nut won't seal a DIN 2353 body, and it won't work the other way around either. To bridge the two systems, you need a purpose-made JIC-to-DIN 2353 swivel adapter, one that presents a 37° flare on one end and a 24° cone on the other. JIC is dimensionally equivalent to the metric 37° flare of ISO 8434-2, and it shares the 37° cone with the aerospace AN fitting, though thread tolerances differ between them. DIN 2353, meanwhile, is equivalent to ISO 8434-1. Crestflo's compression tube fittings are performance-qualified to ASTM F1387, which allows drop-in interchange within a standard. Need a mapping from a specific competitor series to the Crestflo equivalent? Ask the engineering team for a cross-reference: request your JIC or DIN 2353 cross-reference.

Which Should You Specify: JIC or DIN 2353?

Neither standard beats the other outright. The right choice depends on the mating equipment and the shop doing the work. Specify JIC when the equipment follows North American or SAE practice, when flaring tooling is already on hand, and when a reusable inch-sized flare joint is what's wanted. Specify DIN 2353 when the equipment is European-OEM, when flaring isn't desired, when high vibration or pull-out resistance matters, or when metric tube stock and metric ports are the norm.

JIC comes with known trade-offs. The tube has to be flared before assembly. The metal-to-metal flare is sensitive to over-torque, under-torque, and flare damage. And inch dash sizing doesn't line up with metric European specs. The table below lays out the common cases.

Materials for JIC & DIN 2353 Fittings: 316L to Inconel

JIC and DIN 2353 fittings share the same lineup of instrumentation alloys. For general service, 304/304L and 316/316L stainless cover most needs. Chloride exposure or heavier corrosion duty calls for something tougher, and that's where 904L, Duplex 2205, Super Duplex 2507, 254 SMO, AL-6XN, and Alloy 20 come in. Inconel, Incoloy, Monel, and Hastelloy nickel alloys handle the most aggressive media. Titanium Gr2 rounds out the range.

Sour service requires a grade that complies with NACE MR0175 / ISO 15156-. See NACE MR0175 sour-service compliance for details. To match a grade against your media, consult the instrumentation fitting materials hub or the 316/316L grade page.

Why Crestflo: One Maker of Both 37° Flare and DIN 2353 Fittings

Crestflo manufactures instrumentation fittings and valves, and it makes both families in the same catalog: 37° flare fittings to ISO 8434-2 and DIN 2353 bite-type fittings, in imperial and metric sizes alike. That's worth noting, because this comparison comes from a company that actually machines both standards, not a reseller favouring one over the other. Fittings are available from 316/316L through 904L, Duplex 2205, Super Duplex 2507, 254 SMO, AL-6XN, Alloy 20, the Inconel/Incoloy/Monel/Hastelloy nickel alloys, and Titanium Gr2, with end connections up to 2″ (50 mm) OD and 37° flare working pressure up to 15,000 psi. Every part is heat-number marked, with EN 10204 3.1 material test certification as standard and 3.2 available on request. Compression tube fittings, for their part, are performance-qualified to ASTM F1387 for drop-in interchange. Crestflo is the instrumentation division of a four-decade-old export house recognized by the Government of India, certified to ISO 9001 / 14001 / 45001 and PED. Product is of Indian origin; US or European melt can be supplied on request, along with full material traceability. Standard items ship from stock. Specials are made to order. Delivery runs six to eight weeks. We Engineer Confidence.

Get a quote for JIC or DIN 2353 fittings in any alloy. Or request a sample to check the fit first.

• Request a quote, JIC or DIN 2353 fittings, any alloy
• Request a sample

Crestflo stocks three product lines worth knowing. There's the 37° JIC flare fittings, the JIC-37 tube fittings, and the DIN 2353 bite-type fittings.

Reviewed by the Crestflo Engineering Team US contact: sales@crestflousa.com · +1 346 594 9005 · Houston, TX.

Frequently Asked Questions: JIC vs DIN 2353

Related Resources

• JIC vs SAE O-ring boss (ORB)
• Metric vs imperial tube fittings
• Single vs double vs ferrule-less compression fittings
• Cone-and-thread vs compression fittings
• Thread identification guide
• Pressure–temperature derating
• ASTM F1387 interchange qualification
• Hydraulic fitting applications
• 37° JIC flare fittings · DIN 2353 tube fittings
• Instrumentation resources hub