Adaptors

Hydraulic Adaptors for BSP, JIC, NPT, ORFS and Metric Connections

Hydraulic adaptors connect components that use different thread sizes, standards or port configurations. They are widely used between hoses, pumps, valves, motors, cylinders, rigid pipework and manifold blocks.

The HPM Hydraulic catalogue includes adaptors for multiple hydraulic connection systems, including products combining standards such as BSP, NPT, JIC, SAE, ORFS and metric threads. Current products also include tees, swivels, flange connections and reusable hose fittings. ([hpmhydraulic.com](https://hpmhydraulic.com/adaptors/16445-))

Hydraulic Thread Standards

BSP and BSPT

BSP connections are widely used in European hydraulic systems. Parallel BSP threads usually require a dedicated sealing face, bonded seal or other sealing method.

BSPT uses a tapered thread and should not be assumed to behave the same way as BSPP.

NPT

NPT is a tapered pipe-thread system commonly used in North American and industrial applications. Sealing is achieved through thread interference together with an appropriate sealing method.

JIC 37-Degree Flare

JIC hydraulic fittings use a 37-degree metal flare for sealing. They are common in mobile and industrial hydraulics and are available in straight, elbow, tee and swivel configurations.

ORFS

ORFS – O-Ring Face Seal connections use a flat sealing face combined with an O-ring. This design is widely used where strong resistance to leakage and vibration is required.

SAE and Metric Connections

SAE and metric systems cover several connection types, including straight-thread O-ring ports and metric tube fittings. Exact thread size alone is not enough to identify the connection.

Male-to-Male, Male-to-Female and Female Adaptors

Adaptors can combine different connection genders depending on the installation.

Typical configurations include:

• male-to-male adaptors,
• male-to-female adaptors,
• female-to-female connectors,
• straight unions,
• reducers and expanders.

HPM currently lists products such as 3/4 BSP x 1 inch NPT male/male adaptors and other mixed-standard connection parts. ([hpmhydraulic.com](https://hpmhydraulic.com/spare-parts-for-hydraulic-pumps/14987-))

Hydraulic Tees and Branch Connections

A hydraulic tee divides or combines flow between multiple circuit branches. Correct port sizing and pressure rating are essential because the fitting becomes part of the pressure-bearing hydraulic circuit.

The HPM catalogue includes BSP male tees as well as mixed fitting configurations. ([hpmhydraulic.com](https://hpmhydraulic.com/adaptors/16445-))

90-Degree and 45-Degree Adaptors

Angled adaptors allow hose and pipe routing where a straight connection would cause excessive bending or interfere with nearby components.

Using the correct elbow can help reduce hose stress and create a cleaner installation, but every additional fitting also creates a potential pressure-drop and leakage point.

Swivel Hydraulic Fittings

Swivel fittings simplify assembly by allowing the connection to be oriented without twisting the hose. Some designs also accommodate limited movement, depending on the intended application.

A swivel assembly must still match the thread, sealing face, pressure rating and hose type.

Hydraulic Flange Adaptors

Larger hydraulic lines and high-flow circuits often use flange connections rather than threaded ports. Flange adaptors can connect a flanged component to hose, pipe or another connection standard.

Verify flange series, nominal size, bolt pattern and pressure class before installation.

How to Identify an Unknown Hydraulic Thread

Do not rely only on outside diameter. To identify an unknown hydraulic connection, check:

• male or female thread,
• outside or inside thread diameter,
• thread pitch or threads per inch,
• parallel or tapered form,
• flare angle,
• presence of an O-ring or sealing cone.

A thread gauge and caliper are useful when the original part number is unavailable.

Sealing Methods in Hydraulic Adaptors

Different fittings seal in different locations. Depending on design, sealing may occur through:

• metal-to-metal flare,
• O-ring face seal,
• O-ring boss,
• bonded seal,
• tapered thread.

Using sealing tape or thread sealant on a connection that seals at a flare or O-ring face does not correct an incompatible fitting.

Common Causes of Hydraulic Fitting Leaks

• mixed thread standards,
• damaged flare or sealing face,
• incorrect O-ring,
• cross-threading,
• under-tightening,
• excessive tightening,
• side load from poor hose routing,
• vibration or mechanical damage.

Hydraulic Adaptors from HPM Hydraulic

HPM Hydraulic supplies hydraulic adaptors and fitting components for mobile, industrial and machinery applications. The range covers multiple thread standards, hose connections, tees, swivels and conversion fittings.

When selecting an adaptor, match the complete connection specification rather than only the nominal size.

FAQ – Hydraulic Adaptors

What is a hydraulic adaptor?

A hydraulic adaptor connects two hydraulic components or lines that use different sizes, thread standards or connection types.

How can I tell whether a thread is BSP or NPT?

Compare thread form, pitch and taper. Their geometry differs, so outside diameter alone is not sufficient.

What does JIC mean?

JIC is a hydraulic connection standard using a 37-degree flare sealing surface.

What does ORFS mean?

ORFS stands for O-Ring Face Seal. It uses a flat face and O-ring to create the hydraulic seal.

Can I use thread seal tape on JIC fittings?

The JIC connection seals at the flare, not on the threads. Thread tape is therefore not the intended sealing method for the JIC flare interface.

Why is my hydraulic adaptor leaking?

Check that the thread standard, sealing face, O-ring and tightening method all match the original system.