Hydraulic Fitting Identification & Thread Data

Thread identification, dimensional data, and specifications for JIC, NPT, BSP, ORFS, DIN, and JIS hydraulic fitting standards.

Identifying a hydraulic fitting starts with the thread. Measure the outside diameter, count the threads per inch (or measure the pitch in millimeters), and check the seat angle. Each standard below includes thread tables with dash sizes, tube OD, thread callouts, wrench sizes, and identification tips.

JIC and NPT are the most common in North America. BSP dominates in Europe, the Middle East, and most of Asia outside Japan. DIN is the European metric standard. ORFS is the premium choice for zero-leak systems. JIS is specific to Japanese equipment.

The most common identification mistake is confusing JIC with NPT. Both are North American standards but JIC uses a 37-degree flare with straight threads while NPT uses tapered pipe threads. They cannot be interchanged. The second most common mistake is confusing BSP with NPT. Both are pipe thread standards with similar sizing conventions, but the thread angle differs (55 degrees for BSP vs 60 degrees for NPT) and they will not seal properly if cross-threaded.

Fitting Standards by Region

JIC (SAE J514)

The most common hydraulic fitting in North America. 37-degree flare, straight threads, reusable without replacing seals.

NPT

Tapered pipe threads found everywhere in plumbing and pneumatics. Seals by thread deformation. Not reliably reusable.

BSP (BSPP/BSPT)

The international counterpart to NPT. 55-degree Whitworth thread angle. NOT interchangeable with NPT despite similar sizes.

ORFS (SAE J1453)

The leak-proof fitting. O-ring seals on a flat face. Best for high vibration and zero-leak requirements. More expensive than JIC.

DIN 2353 / ISO 8434-1

European standard bite-type fittings. Metric threads with a 24-degree cone and cutting ring. Common on German and Scandinavian machinery.

JIS B 2351

Japanese standard fittings. 30-degree flare with metric threads. Found on Komatsu, Kobelco, Hitachi, and other Japanese equipment.

SAE ORB (O-Ring Boss)

Straight-thread O-ring port fitting. The most common hydraulic port standard in North American mobile and industrial equipment.

Comparisons and Guides

Fitting Comparisons

Side-by-side comparisons of commonly confused fitting standards. JIC vs NPT, BSP vs NPT, ORFS vs JIC.

Fitting Guides

How to identify hydraulic fittings by thread type, measure threads, and use sizing charts.

External Resources