Hydraulic Thread Identification Chart

What it is

Hydraulic fittings seal in one of three ways: on the threads (tapered threads), on a cone or flare seat (metal to metal), or with an O-ring. To match a fitting you need both the thread and the seal type. SAE J514 covers JIC 37° flare fittings and related connections. SAE J1926 covers the straight-thread O-ring boss (ORB) port.

How to identify

1. Look at the sealing surface. Is there a flare seat, a flat face with an O-ring groove, an O-ring on the threads, or only tapered threads?
2. Check whether the threads are tapered or straight. A tapered thread gets larger toward the body.
3. Measure the thread outside diameter with calipers and check the pitch with a thread gauge.
4. For flare fittings, check the seat angle with a seat gauge: 37° (JIC) and 45° (SAE flare) look alike.
5. Match the measured size to the table.

Connection types

Dash sizes for JIC and ORB

Key points

• The dash number is the tube OD in sixteenths of an inch: -8 is 8/16, or 1/2 in.
• JIC and ORB of the same dash size share a thread but seal differently. Do not cross them.
• Never use thread sealant or tape on JIC, ORB or ORFS connections. They seal on the seat or O-ring.
• Pressure ratings depend on fitting type, size and material. Use the fitting maker's data.

Common mistakes

• Mating a 37° JIC fitting with a 45° SAE flare. It may start but will leak.
• Mixing NPT and BSPT, which have different thread angles and pitches in some sizes.
• Reusing flattened O-rings on ORB and ORFS fittings.

Governing standards: SAE J514 (hydraulic tube fittings); SAE J1926 (connections for general use and fluid power, ports and stud ends with ASME B1.1 threads and O-ring sealing); SAE J1453 (O-ring face seal fittings); ASME B1.20.1 and B1.20.3 for pipe threads.

Reference only. Verify against the current governing code or standard, the manufacturer's data and the project documents before use. Apps for Distributors disclaims liability arising from reliance on this reference.