JIC fittings — 37° flare connections per SAE J514 — are the most common hydraulic fitting in North American equipment. The seal is metal-to-metal: the flared tube or hose-end nose seats against the fitting's 37° cone, no O-ring required. That makes JIC reusable, vibration-tolerant, and easy to field-service, which is exactly why it dominates mobile equipment and general hydraulics.

Dash Sizes & Threads

JIC sizes are called out in dashes — sixteenths of an inch of tube OD. The thread is UNF:

JIC vs AN, ORFS, and NPT

AN fittings share the 37° flare and threads but are made to tighter aerospace tolerances — dimensionally interchangeable for most industrial purposes. ORFS (O-ring face seal) uses a flat face with an elastomer O-ring; it seals tighter under severe vibration and is the pick where zero-leak matters, but costs more. NPT is a tapered pipe thread that seals on the threads themselves — fine for ports and plumbing, but prone to loosening under vibration and not reusable like JIC. Never force a 45° SAE flare fitting onto a 37° JIC seat: some sizes share threads and will assemble, then leak.

Assembly That Doesn't Leak

JIC leaks come from three causes: over-torque that cracks the flare, under-torque that never seats it, and damaged noses. Use the flats-from-wrench-resistance (FFWR) method — hand-tight plus the specified flats (typically 1 to 2 flats depending on size) — or a torque chart. Inspect the cone and flare for scoring before every reassembly, and replace fittings with visible damage rather than tightening harder.

Hose Assemblies Built to Spec

We crimp hydraulic hose with JIC, ORFS, NPT, and metric ends in-house — most builds go out same day, pressure-tested and tagged. Put your dash size, ends, length, and quantity in the quote form at the top of the page, or visit our hydraulic hose page — quotes back in 1–2 business hours.