DELPHI FITTINGS
The Field Guide: ORB vs. ORFS Fittings
In high-pressure hydraulics, a leak isn't just a drip—it's a failure. It means downtime, a safety hazard, and a callback that costs you money. When old-school pipe threads (NPT) and flare fittings (JIC) start weeping under pressure and vibration, it's time to step up to a modern O-ring seal. The two champs in this arena are O-Ring Boss (ORB) and O-Ring Face Seal (ORFS). Knowing the difference, and when to use each, is what separates the pros from the amateurs.
What is an O-Ring Boss (ORB) Fitting? The Port-Sealing Pro.
The SAE J1926 O-Ring Boss fitting is a smart, tough way to seal a port. Think of it as the professional replacement for an NPT plug or adapter. The design is dead simple: the straight UNF threads are only there for clamping muscle. The actual sealing is done by a tough O-ring that sits in a groove at the base of the male threads. When you tighten the fitting, that O-ring is squeezed into a chamfered "bunker" inside the female port (the "boss"). The seal is contained, protected, and incredibly reliable against leaks.
What is an ORFS Fitting? The Zero-Leak Champion.
If ORB is a huge step up, then the SAE J1453 O-Ring Face Seal is the top of the pyramid. This is the fitting you use when a leak is absolutely not an option. Instead of sealing inside a port, the ORFS system seals on the very end of the fitting. The male end has a perfectly flat face with a groove for the O-ring. The female swivel nut has a matching flat face. When you tighten the nut, the O-ring is compressed between these two flat faces, creating a seal that’s as close to bombproof as you can get in hydraulics.
The Showdown: ORB vs. ORFS at a Glance
Here’s the straight-up comparison to help you choose the right fitting for the job.
| Feature | O-Ring Boss (ORB) | O-Ring Face Seal (ORFS) |
|---|---|---|
| Primary Job | Sealing a fitting INTO a port (pumps, valves, cylinders). | Connecting two hose or tube ends TO EACH OTHER. |
| How It Seals | O-ring at the base of the male thread, compressed into a chamfer INSIDE the port. | O-ring in the flat face of the male end, compressed against the flat face of the female end. |
| Best For | High-pressure, static port connections. Excellent vibration resistance. | Extreme high-pressure and the highest vibration environments. Mission-critical lines. |
| Key Advantage | Massive upgrade in reliability over NPT. Extremely common and easy to find. | Considered the ultimate leak-proof connection. Zero-clearance design is a huge time-saver for maintenance. |
| SAE Standard | SAE J1926 | SAE J1453 |
The Bottom Line for Your Business
Stocking both ORB and ORFS fittings is a smart move. But knowing when to recommend each is what makes you an invaluable partner instead of just another parts guy. When your customer calls with a leak, don't just sell them a replacement—ask them where it failed. If it was a pipe thread in a port, upgrade them to ORB. If it was a line-to-line connection on a machine that shakes itself to pieces, sell them the permanent fix with ORFS. That’s how you solve real problems and build a business that lasts. When you're ready to stock the parts that work, give us a call at the factory.