Direct lookup · SAE J514 37° flare
JIC 37° Fitting Size and Thread Chart
Find the dash size, tube OD, thread, TPI and nominal male thread OD—without using the calculator.
Common sizes: -6 = 3/8 in tube, 9/16-18 thread; -8 = 1/2 in tube, 3/4-16; -12 = 3/4 in tube, 1-1/16-12.
No JIC size matches that search. Clear the filter or check the thread pitch.
On narrow screens, swipe the chart sideways to see thread diameter and the Use button →
Scroll horizontally for additional columns. The dash-size column remains visible while scrolling.
| Select | ||||||
|---|---|---|---|---|---|---|
| -2 | 1/8 in | 5/16-24 UNF | 24 | 0.3125 | 7.94 | |
| -3 | 3/16 in | 3/8-24 UNF | 24 | 0.3750 | 9.53 | |
| -4 | 1/4 in | 7/16-20 UNF | 20 | 0.4375 | 11.11 | |
| -5 | 5/16 in | 1/2-20 UNF | 20 | 0.5000 | 12.70 | |
| -6 | 3/8 in | 9/16-18 UNF | 18 | 0.5625 | 14.29 | |
| -8 | 1/2 in | 3/4-16 UNF | 16 | 0.7500 | 19.05 | |
| -10 | 5/8 in | 7/8-14 UNF | 14 | 0.8750 | 22.23 | |
| -12 | 3/4 in | 1-1/16-12 UN | 12 | 1.0625 | 26.99 | |
| -14 | 7/8 in | 1-3/16-12 UN | 12 | 1.1875 | 30.16 | |
| -16 | 1 in | 1-5/16-12 UN | 12 | 1.3125 | 33.34 | |
| -20 | 1-1/4 in | 1-5/8-12 UN | 12 | 1.6250 | 41.27 | |
| -24 | 1-1/2 in | 1-7/8-12 UN | 12 | 1.8750 | 47.62 | |
| -32 | 2 in | 2-1/2-12 UN | 12 | 2.5000 | 63.50 |
Read correctly: JIC dash size means nominal tube outside diameter in 1/16-in units; it is not the male thread diameter. Male Ø is the nominal external thread major diameter. Confirm actual thread form, TPI and 37° seat before using a connection.
Reverse identification
Identify a JIC Size From Thread Measurements
Measure the male thread across its outer crests, choose the unit and confirm threads per inch (TPI).
Example: 0.750 in + 16 TPI points to nominal JIC -8 (3/4-16). A nearest size is not proof of a 37° seat.
Static example: 0.750 in and 16 TPI corresponds to nominal -8 (3/4-16 UNF, 1/2-in tube OD). The chart above remains available without JavaScript.
Verification required: The finder compares nominal male diameters for the selected TPI. Its 0.030-in screening flag is not a thread acceptance tolerance. Confirm 37° metal-seat geometry and the fitting specification.
Geometry guide
Where to Measure the Male Thread and 37° Flare
Straight threads retain the joint; the opposing 37° metal seats create the primary seal.
- Chosen dash size
- -8
- Unified thread
- 3/4-16 UNF
- Nominal male OD
- 0.7500 in · 19.05 mm
- Nominal tube OD
- 1/2 in · 12.70 mm
- Sealing mechanism
- 37° mating metal seats
How to Measure and Identify a JIC Fitting
- Depressurize and isolate equipment. Follow manufacturer lockout and pressure-release procedures; never loosen a pressurized hydraulic fitting.
- Inspect the connection. Check the external threads and 37° sealing surfaces for damage, corrosion, contamination or distortion.
- Measure the male thread outside diameter. Place calipers across opposite thread crests and record inches or millimeters. Do not use the wrench hex width.
- Count thread pitch. Use an appropriate thread-pitch gauge to establish the exact TPI. A similar OD with the wrong TPI is not a match.
- Cross-reference the chart or measurement finder. Locate the nominal thread diameter and pitch together; then verify the 37° seat and the applicable fitting specification.
Female JIC identification: a female thread ID by itself is not equivalent to a male major OD. Use an appropriate verified male reference, thread gauge and seat gauge, or manufacturer documentation.
JIC Dash Size vs. Tube OD vs. Thread Size
The dash number refers to nominal tube outside diameter in sixteenths of an inch. For example, a -8 JIC end corresponds to 8/16 in = 1/2 in tube OD, but the male thread is 3/4-16 UNF. A -12 JIC end corresponds to 3/4 in tube OD, but uses a 1-1/16-12 UN thread.
Do not assume a hose assembly with “-8” in its part number has a -8 JIC port. Dash numbers can identify hose ID, tube OD, fitting ends or an adapter’s separate ends depending on product context.
JIC vs. AN, SAE 45° flare, ORB and NPT
| Connection | How it seals | Key distinction |
|---|---|---|
| JIC 37° | 37° metal flare-to-seat contact | Straight UN / UNF retention threads; verify 37° seat. |
| SAE 45° flare | 45° mating flare seats | Some threads can appear identical, but seats are not interchangeable. |
| SAE ORB | O-ring at straight-thread port | Common thread dimensions do not make the port a JIC flare. |
| AN 37° | 37° flare geometry | Application and qualification requirements may differ from industrial JIC. |
| NPT / NPTF | Tapered pipe-thread sealing system | Not the same as a straight-thread 37° flare joint. |
JIC Fitting Size Examples
Example: JIC -6
The dash size means nominal 6/16 = 3/8 in tube OD (9.53 mm). The chart lists 9/16-18 UNF and nominal male thread OD 0.5625 in (14.29 mm).
Example: measured 19.05 mm and 16 TPI
19.05 mm ÷ 25.4 = 0.7500 in. The matching nominal male diameter with 16 TPI is JIC -8: 3/4-16 UNF and nominal 1/2 in tube OD. Inspect the seat before use.
Safety and Compatibility Limits
Important: Nominal chart dimensions alone cannot establish mechanical interchangeability or pressure service suitability. Verify the fitting’s 37° seat, TPI, straight thread, actual dimensional tolerances, manufacturer specifications and mating geometry.
- Do not connect parts solely because their threads engage.
- Replace damaged flares, threads, or mating surfaces; do not force connections.
- Use product-specific torque, material, temperature and pressure ratings rather than inferring them from dash size.
- Never inspect, tighten, or disconnect a fitting while the hydraulic system is pressurized.
JIC Fitting Standards and Reference Sources
Reference review: October 8, 2026 · 13 representative size rows · Nominal identification values only
The 13-row dash, tube OD and thread cross-reference is a limited identification reference checked against public fitting-thread charts. Metric values are calculated from canonical inches with 1 in = 25.4 mm, and thread pitch equals 25.4 ÷ TPI. We do not reproduce copyrighted standards tables or dimensional acceptance tolerances.
- SAE J514-1_202606 — 37-Degree Flared Fittings (June 22, 2026)Official current revision and application scope; not a reproduction of the paid standard’s dimensions.
- Titan Fittings — US Thread Chart: JIC 37° FlarePublished fitting-end crosswalk and distinction between straight threads and 37° sealing seats.
- Hydraulics Direct — Fitting Thread ChartIndependent check of 13 nominal JIC dash-to-thread sizes and cautions about 45° flares.
- ISO/FDIS 8434-2 — 37° Flared ConnectorsEdition 3 final draft under approval as checked October 2026; not stated here as a published replacement for ISO 8434-2:2007.
Data scope and calculation method
- Reference range
- 13 listed JIC sizes, -2 to -32; no unlisted sizes invented
- Nominal fields
- Dash size, tube OD, UN / UNF designation, TPI, male major OD
- Calculated fields
- Metric OD = inch OD × 25.4; pitch = 25.4 ÷ TPI
- Not included
- Acceptance tolerances, material, torque, pressure rating, hose ID, manufacturer-specific qualifications
- Publisher
- Turn2Engineering
JIC Fitting Size Chart FAQs
JIC -6 is a 9/16-18 UNF straight thread for a 3/8 in nominal tube outside diameter. The sealing seat must also be verified as 37°.
JIC -8 uses a 3/4-16 UNF straight thread and corresponds to 1/2 in nominal tube outside diameter. The nominal male thread major diameter is 0.7500 in (19.05 mm).
Dash size refers to the nominal tube OD in sixteenths of an inch. Thread diameter is different: a -8 end refers to 1/2 in tube OD but uses a 3/4-16 thread.
No. Some nominal threads overlap, but their sealing angles are different. Thread engagement by itself does not establish a safe or leak-free connection.
JIC and SAE ORB can share straight thread dimensions but seal in different places. AN uses related 37° flare geometry but may have different specification, materials, and qualification requirements. Verify the exact application.
A female inside-diameter measurement alone is not a reliable substitute for measuring a male major thread diameter. Use the appropriate thread and seat gauges, a verified mating reference, or manufacturer documentation.
No tape is required at the 37° metal-to-metal flare sealing interface. Follow the manufacturer’s installation and sealing instructions; straight threads do not make the primary JIC seal.
Find the Size, Then Verify the Seal
Use the JIC chart to read nominal tube OD and thread by dash size. If the dash is unknown, compare measured male major OD and exact TPI. Before installation, verify the straight threads, 37° flare seat, fitting standard, condition and manufacturer requirements.