Shop Hydraulic Adapters, Fittings & Flanges

Hydraulic adapters, fittings and flanges are what hold a fluid power system together. Adapters join two ports or hose ends that can't connect directly, because their threads or sizes differ or because both ends are the same gender (such as two female ports). Shaped adapters like elbows, tees and crosses also change direction or branch a line. Fittings connect hose, tube and pipe to pumps, valves and cylinders. Flanges bolt larger lines to a port with an O-ring seal where a threaded connection would be hard to tighten or keep tight.

This page is the starting point for all of it: standard hydraulic adapters in straight, 45°, 90°, tee, cross, plug and cap shapes; SAE Code 61 and Code 62 flanges; hose end fittings and quick disconnects; high pressure, instrumentation, flareless bite-type and pneumatic fittings; and the kits, gauges and sealant that go with them. OneHydraulics is a Houston, TX distributor, and every brand we carry is listed on the pages below.

The fastest way to get the right part is to identify the thread first. If you're not sure what you have, start with our Adapter & Thread Identification Guide, ask our Hydraulic AI Assistant, or call 281-941-2310.

Hydraulic AdaptersJIC, NPT, ORB, ORFS, BSPP, BSPT, DIN and metric, shopped by shape: straight, 45°, 90°, tee, cross, plug, cap.Shop Now

Hydraulic FlangesSAE Code 61 and Code 62 split, captive, threaded, butt weld, socket weld and saddle weld flanges.Shop Now

Hose End FittingsHose end fittings organized by hose brand so the fitting matches the hose.Shop Now

Quick Disconnect CouplersCouplers and nipples for connecting and breaking hydraulic lines without tools.Shop Now

High Pressure AdaptersMedium pressure, high pressure, Type M, NPT, BSP and JIC fittings rated up to 60,000 PSI.Shop Now

Instrumentation Tube & Pipe FittingsDouble-ferrule compression tube fittings and 316 stainless NPT pipe fittings for measurement and control lines.Shop Now

Flareless Bite-Type FittingsNut, ferrule and body tube fittings in steel and stainless that seal without flaring the tube.Shop Now

Pneumatic AdaptersPush-in fittings, elbows, tees, banjos and plugs for compressed air systems.Shop Now

Suction & Return AdaptersReservoir suction, return and filler-breather adapters and mounting flanges.Shop Now

Adapter, Seal & Thread Gauge KitsAdapter kits, thread ID kits and O-ring seal kits for the shop or service truck.Shop Now

Weld CouplingsWeld-on threaded couplings for adding a port to a tank, reservoir or pipe.Shop Now

Thread SealantTape and liquid sealants for tapered pipe-thread connections.Shop Now

How to Choose a Hydraulic Adapter

Work through four questions in this order, for each end of the adapter:

Thread family. JIC, NPT, ORB, ORFS, BSPP, BSPT, DIN or metric. This is where most wrong orders come from. Families that look alike, like NPT and BSPT, or JIC and 45° SAE flare, are not interchangeable.
Gender and style. Male or female, and on female ends, fixed or swivel. Swivel ends let you tighten an adapter without turning the hose or tube it's attached to.
Shape. Straight, 45°, 90°, tee, cross, plug or cap. Choose based on routing and clearance.
Size and material. Hydraulic sizes are usually given as dash numbers in sixteenths of an inch, so -08 is 1/2". The thread you measure won't always match that number, and the adapter guide has charts that line up thread callouts with dash and inch sizes.

Hydraulic Thread Families at a Glance

Here's a quick summary of each family. To identify a thread step by step, see the Adapter & Thread Identification Guide.

NPT / NPTF is the US tapered pipe thread. It seals as the threads wedge together. Most NPT adapters on our site are NPTF (dryseal) but are listed simply as "NPT."
JIC (SAE J514) has a 37° flare seat and is one of the most common hose-end connections in North American fluid power.
ORB (SAE J1926) is a straight thread that seals with an O-ring in a chamfered port. It's often labeled just "SAE."
ORFS (SAE J1453) seals with an O-ring in the male face pressed against a flat female face.
BSPP and BSPT are British parallel ("G") and tapered ("R") threads with a 55° flank angle. They come in inch sizes but don't match NPT.
DIN 24° tube fittings (ISO 8434-1) use a 24° cone with a cutting ring and come in LL, L and S pressure series. Metric port fittings (ISO 9974) follow the BSPP (ISO 1179) stud-end design and seal with an O-ring and washer, an elastomeric seal or a bonded washer, not on the threads.

Thread family	Standard	Seal method	Typical use	Shop
NPT / NPTF	ASME B1.20.1 / B1.20.3 (60° thread)	Tapered thread interference; sealant on NPT, dryseal on NPTF	Pumps, valves, manifolds and general pipe ports in North America	Shop NPT adapters
JIC 37°	SAE J514	Metal-to-metal 37° flare and cone	Hose ends and tube connections across mobile and industrial hydraulics	Shop JIC adapters
ORB (SAE O-ring boss)	SAE J1926	O-ring compressed into a chamfered straight-thread port	Pump, valve and cylinder ports	Shop ORB adapters
ORFS	SAE J1453	O-ring in the male face against a flat female face	High-vibration lines where leak control is critical	Shop ORFS adapters
BSPP ("G")	ISO 228-1 (55° thread)	30° cone seat (swivel), or O-ring or bonded washer at a port	European and Asian equipment	Shop BSPP adapters
BSPT ("R")	ISO 7-1 (55° thread)	Tapered thread with sealant	European and Asian equipment, pipe ports	Shop BSPT adapters
DIN 24° / metric	ISO 8434-1 (DIN 24° cone); ISO 9974 (metric ports)	Cutting ring on a 24° cone; metric ports (ISO 9974) seal with an O-ring and washer, an elastomeric seal or a bonded washer	European equipment; LL, L and S pressure series	Shop DIN adapters
4-bolt flange	SAE J518 Code 61 / Code 62	O-ring in the flange head against a flat port face	Large-bore pump, motor and pipe connections	Shop flanges

Sealing Methods Compared

The thread holds the joint together. On most families, the seal itself happens somewhere else, and that affects how the joint behaves in service:

Tapered thread (NPT, BSPT): seals as the male and female threads wedge together and deform slightly when tightened. Standard NPT and BSPT need thread sealant or PTFE tape to complete the seal; NPTF dryseal is made to seal without it, though sealant is often still used as a lubricant and backup. Best for joints you assemble once. Repeated tightening wears the threads, and overtightening can crack a port.
37° flare (JIC): a metal-to-metal seal between the male flare and the female cone. Easy to take apart and reassemble.
O-ring boss (ORB): an O-ring compresses into a chamfer at the port. Reliable and reusable, and the usual choice for pump, valve and cylinder ports.
O-ring face seal (ORFS): an O-ring compresses against a flat face. Widely regarded as the most leak-resistant threaded connection, especially where vibration is heavy.
Flange (SAE J518): an O-ring in the flange head seals against a flat port face, and four bolts hold the joint. It's used on larger lines and on ports where a large wrench won't fit.

Hydraulic Flanges: Code 61, Code 62 and Weld Styles

SAE J518 4-bolt flanges come in two pressure classes. Code 61 is the standard 3,000 PSI flange. Code 62 is the 6,000 PSI version, with a larger head diameter and wider bolt spacing. Never mix Code 61 and Code 62 parts on one connection.

Choose the flange style for how it attaches to the line:

Split flanges slide on from the side around a flange head. They're the usual choice for hose connections.
Captive flanges stay on the tube or pipe assembly, so they can't get lost during service.
Butt weld flanges give deeper weld penetration and a stronger joint. Socket weld flanges are easier to weld. Saddle weld flanges add a new port to an existing pipe.
Threaded flanges, blanking flanges and flange plugs cover adapting and closing off ports.

The Flange Guide covers each style in more detail.

Pressure Ratings & Materials

A pressure rating applies to one specific fitting in one specific size and material. It doesn't apply to a whole thread family, so check the rating on each product page and size every component in the line to your system's maximum working pressure. A few guidelines:

Standard hydraulic adapters come in carbon steel and stainless steel. Plated carbon steel covers most mobile and industrial work, including general outdoor use. Choose stainless for corrosive, marine/offshore, chemical or washdown service.
Flanges are rated by class: 3,000 PSI for Code 61 and 6,000 PSI for Code 62.
High pressure adapters cover ratings up to 60,000 PSI in medium pressure, high pressure, Type M, NPT, BSP and JIC connections. Don't substitute standard hydraulic adapters in these lines.
Instrumentation fittings are stainless steel double-ferrule compression tube fittings and 316 stainless NPT pipe fittings, for process measurement and control lines.

Kits, Gauges, Seals & Sealant

If you service mixed equipment, a few shop items pay for themselves quickly:

Thread gauge ID kits for JIC, NPT, ORB, ORFS, BSP and metric threads. Measure pitch and diameter before you order.
Adapter kits that cover DIN, BSPP, metric, JIC, NPT and Komatsu connections for field repairs.
O-ring seal kits for male ORB, ORFS, BSPP and metric bonded seals, plus Code 61 and Code 62 flange seals. Replacement O-rings, bonded seals, washers and retaining rings are listed under Adapter Accessories. Nuts and DIN cutting rings have their own pages.
Thread sealant for tapered NPT and BSPT joints. JIC, ORB and ORFS seal on the flare or O-ring, so they don't need sealant on the threads.

Frequently Asked Questions

What's the difference between a hydraulic adapter and a hydraulic fitting?

"Fitting" is the general term for any component that connects hose, tube or pipe in a hydraulic system, including hose ends that crimp onto hose. An adapter is a fitting with a connection on each end that joins two components that can't connect directly, because their threads or sizes differ or both ends are the same gender, such as a male JIC to male NPT. Use the hose end fittings page for parts that attach to hose, and the adapters pages for everything that joins one threaded end to another.

How do I identify the thread on my fitting?

First check whether the thread is tapered or parallel. Then measure threads per inch, or pitch in millimeters for metric, with a thread gauge. Next, measure the outside diameter of a male thread or the inside diameter of a female thread with calipers, and match the result to a thread chart. Finally, look at the sealing surface (flare angle, O-ring or cone) to narrow down the family. Our Adapter & Thread Identification Guide walks through each step, and a thread gauge kit makes it much faster.

Can I connect a JIC 37° fitting to a 45° SAE flare fitting?

No. In the -02, -03, -04, -05, -08 and -10 sizes, 37° JIC and 45° SAE flare fittings use the same threads, so they screw together, but the seat angles are different and the joint will leak. JIC 37° is the fluid power standard. 45° flare is more common in automotive, refrigeration and truck lines. Check the seat angle before you install.

Are NPT and BSP threads interchangeable?

No. NPT has a 60° thread angle and BSP has 55°, and in most sizes the pitch and outside diameter are also different. The threads may start but won't seal reliably. Within the British family, a male BSPT can thread into a fixed female BSPP port, but not into a BSPP swivel, because the swivel's cone seat gets in the way.

What's the difference between ORB and ORFS?

Both use an O-ring and a straight thread, but the O-ring sits in a different place. On ORB (SAE J1926), the O-ring is on the male thread and compresses into a chamfer in the port. On ORFS (SAE J1453), the O-ring sits in the flat face of the male end and compresses against the flat face of the female. ORB is the common port connection. ORFS is widely regarded as the most leak-resistant choice for hose and tube connections.

What's the difference between Code 61 and Code 62 flanges?

Both are SAE J518 4-bolt flanges that seal with an O-ring against a flat port face. Code 61 is the standard 3,000 PSI flange. Code 62 is rated 6,000 PSI and has a larger flange head diameter and wider bolt spacing. They don't interchange, so match the flange code to the port.

Do I need thread sealant on hydraulic fittings?

Only on tapered threads. NPT and BSPT seal as the male and female threads wedge together and deform slightly, and standard NPT and BSPT need tape or liquid sealant to complete that seal. NPTF is designed to seal dry, though sealant is often still used as a lubricant and backup. JIC, ORB and ORFS seal at the flare or O-ring rather than the threads, so they don't need sealant on the threads.

What's the difference between NPT and NPTF?

Both are US tapered pipe threads. Standard NPT leaves a small gap between the thread crests and roots, so it needs sealant. NPTF (National Pipe Tapered Fuel) is made so the crests and roots meet and deform, giving a dry seal. Most NPT adapters sold on OneHydraulics.com are NPTF, even though they're listed as "NPT."