JIC Fittings Guide › How to Identify a JIC Fitting

How to Identify a JIC Fitting (Step by Step)

Ordering the wrong fitting is expensive: downtime, return shipping, and leaks from mismatched seats. This guide shows how to positively identify a JIC 37° flare fitting and find its dash size in about five minutes with three inexpensive tools. When you have the size, you can request a quote right here. The main JIC fittings guide has the summary size chart.

Tools You Need

• Calipers (dial or digital, inch and mm) for thread OD and ID.
• Inch thread pitch gauge to count threads per inch (a metric gauge too, if you work on European or Asian equipment).
• Seat angle gauge with 24°, 30°, 37° and 45° blades.

Hydraulic thread identification kits that combine these tools with a reference guide are sold by most hydraulic distributors. McGill Hose's identification guide notes that measured threads can be worn or distorted, so your readings may not match chart values exactly — choose the closest match and confirm with the pitch gauge and seat angle.

Step-by-Step Identification

1. Clean the fitting. Wipe threads and sealing surfaces clean. Dirt, paint and thread sealant hide the seat and throw off measurements.
2. Inspect the sealing surface. Look for a 37° cone on the male nose or inside the female (JIC/SAE 37°), a flat face with an O-ring groove (ORFS), an O-ring on the thread shoulder (O-ring boss port), or threads running to the end with no seat (pipe thread such as NPT).
3. Check the seat angle with a seat angle gauge. Hold a 24°/30°/37°/45° seat gauge against the cone. If the 37° blade sits flush, it is JIC/SAE 37° (or AN). If 45° fits, it is SAE 45° flare; 24° indicates metric DIN cone fittings.
4. Measure the thread diameter with calipers. Measure the male thread OD across the crests, or the female thread ID across the inner crests. Compare with the chart: about 0.75" male OD (0.69" female ID) indicates 3/4-16.
5. Count threads per inch with a pitch gauge. Use an inch thread pitch gauge until a blade seats with no light showing. JIC uses 24, 20, 18, 16, 14 or 12 TPI.
6. Confirm the threads are straight. Measure the OD at the first and last full threads. JIC threads are parallel; if the diameter shrinks toward the end, it is a tapered pipe thread.
7. Match to the dash size. Look up thread size and pitch in the JIC chart to get the dash size, e.g. 3/4-16 is -8 for 1/2" OD tube.

What the Sealing Surface Tells You

JIC Thread Reference

Values from SAE J514 thread sizes; male OD and female ID are approximate measured values as published in McGill Hose's identification guide.

See the JIC thread size chart for metric equivalents.

Common Mix-Ups and How to Avoid Them

JIC vs SAE 45° flare

In sizes -2, -3, -4, -5, -8 and -10, the SAE 37° and SAE 45° flare threads are identical, according to McGill Hose's guide. The nut will thread on but the seats will not seal. The seat gauge is the only reliable check.

JIC vs ORFS

A -6 JIC (9/16-18) shares its thread with a -4 ORFS. Check for the flat O-ring face. More in JIC vs ORFS.

JIC vs NPT

Both 18 and 14 TPI appear in NPT and JIC. Check for taper and the 37° nose. More in JIC vs NPT.

JIC vs AN

AN and JIC are dimensionally identical, so measurement will not separate them — look for stamped AN/MS part numbers and anodized aluminum. See JIC vs AN.

Measuring Tips

• Measure across several points and use the largest consistent reading for male OD; plating and wear reduce it.
• For female threads, measure ID across the crests, not into the roots.
• Use a light behind the pitch gauge — the correct blade shows no gaps.
• Measure the tube OD too; the dash size is tube OD in sixteenths of an inch.
• Record both ends of adapters, since each end can be a different type.

Writing a Clear Quote Request

Once identified, describe each end in order: type, dash size, gender, and configuration — e.g. "-6 JIC female swivel × -6 ORB male, 90° elbow, zinc-plated steel, qty 25". Use the form below or at the top of this page.

Worked Example

Suppose you remove a hose from a log splitter and the male fitting on the valve has a cone-shaped nose. Your seat gauge's 37° blade sits flush against the cone, so it is a 37° flare. Calipers read 0.74" across the crests of the male thread, and the 16 TPI blade of the pitch gauge seats cleanly. The threads measure the same at both ends, so they are straight. Looking up 0.75" and 16 TPI in the chart gives 3/4-16, which is a -8 JIC for 1/2" tube. The reading of 0.74" rather than 0.75" is normal for a worn, plated thread.

Now check the other end. If the body threads into the valve with an O-ring sitting on the shoulder behind straight threads, that end is an SAE O-ring boss (ORB) port, and because ORB shares JIC thread sizes, the same 3/4-16 measurement means it is a -8 ORB. The complete description for ordering is "-8 JIC male × -8 ORB male adapter", plus its shape (straight, 45° or 90°).

FAQ

Related guides

• JIC Fittings Guide (main)
• JIC vs NPT
• JIC vs ORFS
• JIC vs AN
• 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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