Male to Male Hydraulic Adaptors: Thread Types, Uses and Common Mistakes

Male to male hydraulic adaptors are one of the most common types of hydraulic fittings used to connect two female threaded components together. They may look simple, but choosing the wrong adaptor can quickly lead to leaks, poor alignment, thread damage or system downtime.

Whether you are replacing an old fitting, building a hydraulic hose assembly, connecting a valve, pump, cylinder, manifold or port, the key is to match both ends of the adaptor correctly. This means checking the thread type, thread size, sealing method, pressure rating, material and adaptor style before ordering.

If you are not sure which hydraulic adaptor you need, start with our full guide: Find the Right Hydraulic Adaptor First Time .

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Use Flowfit’s Hydraulic Fitting Thread Identification Guide to compare common thread types and measurements before ordering.

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Quick answer

A male to male hydraulic adaptor has male threads on both ends and is used to connect two female hydraulic ports, fittings, hoses or components. To choose the right one, check the thread type, thread size, seal type, pressure rating, material and whether the adaptor needs to be straight, angled, reducing or bulkhead mounted.

Jump to:

1) What is a male to male hydraulic adaptor?
2) Where are male to male hydraulic adaptors used?
3) Common types of male to male hydraulic adaptors
4) Hydraulic thread types to check
5) Why the sealing method matters
6) How to choose the right male to male adaptor
7) Common mistakes to avoid
8) Steel or stainless steel hydraulic adaptors?
9) How to measure a male to male hydraulic adaptor
10) Replacement checklist before ordering
11) Need help finding the right adaptor?

Male to male adaptors Hydraulic adaptors Thread ID guide Adaptor selection guide

1. What Is a Male to Male Hydraulic Adaptor?

A male to male hydraulic adaptor is a fitting with an external male thread on both ends. It is designed to connect two female hydraulic connections together, such as a female hose end to a female port, a female fitting to a valve, or two female threaded components within a hydraulic system.

These adaptors are commonly used in hydraulic repairs, hose assemblies, mobile machinery, agricultural equipment, industrial systems, power packs, cylinders, pumps, valves and manifolds. They are available in different thread combinations, sizes, lengths, materials and shapes depending on the application.

Simple explanation

If both parts you need to connect have female threads, you usually need a male to male hydraulic adaptor between them.

2. Where Are Male to Male Hydraulic Adaptors Used?

Male to male adaptors are used wherever two female hydraulic connections need to be joined safely and securely. They can be used as a straight connector, a thread converter, a reducer or part of a more complex hydraulic hose or pipework layout.

Common use	Why a male to male adaptor may be needed
Hydraulic hose assemblies	To connect a female hose fitting to another female port, fitting or component.
Valves and manifolds	To connect female threaded ports to hydraulic lines or adaptors.
Pumps and cylinders	To adapt the port thread to suit the hose or pipe connection.
Thread conversion	To connect different thread types, such as BSP male to JIC male or BSP male to metric male.
Repairs and replacements	To replace a worn, damaged or incorrect adaptor in an existing hydraulic system.

The adaptor must be suitable for the system pressure, fluid type, thread form and sealing method. A fitting that looks similar may not be safe or leak-free if the details are wrong.

3. Common Types of Male to Male Hydraulic Adaptors

Not all male to male hydraulic adaptors are the same. Some are designed to connect identical threads, while others are used to convert from one thread type or size to another.

Adaptor type	Common use
BSP male x BSP male	Used to connect two BSP female hydraulic fittings or ports.
BSP male x JIC male	Used when one side of the connection is BSP and the other uses a JIC cone-seat connection.
BSP male x metric male	Used to connect BSP hydraulic components to metric threaded ports or fittings.
JIC male x JIC male	Used to connect two female JIC fittings with matching cone seats.
Reducing male to male adaptors	Used when the two female connections are different sizes.
Bulkhead male to male adaptors	Used where a connection needs to pass through a panel, bracket or machine frame.
Elbow male to male adaptors	Used where space is tight or the hose needs to change direction.

Choosing the correct type depends on both ends of the connection. Always identify the thread and sealing style on each side before selecting the adaptor.

Browse the range

View Flowfit’s male to male hydraulic adaptors to compare available thread combinations and adaptor styles.

4. Hydraulic Thread Types to Check

Thread type is one of the most important details when choosing a male to male hydraulic adaptor. Hydraulic threads can look similar, but they are not always interchangeable.

BSP, BSPT, JIC, NPT, ORFS, JIS, SAE and metric threads can all be found in hydraulic systems. Some are parallel, some are tapered, and some seal on a cone, face, washer or O-ring rather than the thread itself.

Thread type	What to check
BSP	Common in UK and European hydraulic systems. Check whether the thread is parallel and how it seals.
BSPT	A tapered BSP thread. Do not assume it is the same as a parallel BSP connection.
JIC	Usually seals on a cone seat. The thread alone is not enough; the seat angle must match.
NPT / NPTF	Common in some hydraulic and industrial systems. Tapered thread form must be correctly identified.
Metric	Check outside diameter, pitch and sealing style before ordering.
ORFS	Uses an O-ring face seal. The face and O-ring condition are critical for leak-free performance.

Important

Do not choose a hydraulic adaptor by thread size alone. Two fittings may look similar but use different thread forms or sealing methods.

5. Why the Sealing Method Matters

A male to male hydraulic adaptor must not only screw into both connections. It must also seal correctly under pressure. This is where many incorrect adaptor choices cause leaks.

Some hydraulic adaptors seal on the thread. Others seal on a bonded seal, washer, cone seat, O-ring or flat face. If the sealing method does not match the mating component, the connection may leak even if the thread appears to fit.

Sealing method	Why it matters
Tapered thread seal	The thread form tightens and seals as it is installed. The correct thread type is essential.
Bonded seal or washer	The adaptor seals against a flat face using the washer or seal.
Cone seat	The cone angle and sealing face must match the female fitting.
O-ring face seal	The O-ring creates the seal against the face of the fitting.
Port seal	The adaptor seals into a hydraulic port using the correct seat, washer or O-ring arrangement.

If you are replacing a male to male adaptor, compare the original fitting carefully. Look at the thread, the seat, the end face and any seal, washer or O-ring that may be fitted.

6. How to Choose the Right Male to Male Hydraulic Adaptor

The best way to choose a male to male hydraulic adaptor is to identify both sides of the connection separately. Do not assume both ends are the same unless you have checked them.

Before choosing an adaptor, check:

Thread type on side one and side two
Thread size on both ends
Thread pitch, especially for metric fittings
Sealing method, such as cone, O-ring, washer or tapered thread
Pressure rating for the hydraulic system
Material, such as zinc-plated steel or stainless steel
Adaptor shape, such as straight, elbow, tee, reducing or bulkhead
Installation space around the hose, port or machine

Helpful tip

If you are unsure, take clear photos of the old adaptor from the side, both threaded ends and next to a ruler or calipers. This can make it much easier to identify the correct replacement.

For a complete step-by-step overview, read our full guide to finding the right hydraulic adaptor first time .

7. Common Mistakes to Avoid

Male to male hydraulic adaptors are often small parts, but the wrong choice can cause major problems. A poor match can lead to leaks, stripped threads, damaged ports, poor hose alignment or repeated breakdowns.

Common mistake	What can happen
Matching the size but not the thread type	The adaptor may partially fit but fail to seal or damage the port.
Ignoring the seal type	The fitting may leak even when fully tightened.
Mixing BSP and NPT	Similar-looking threads can be mistaken for each other and cause sealing issues.
Using the wrong cone-seat adaptor	The sealing faces may not meet correctly, leading to leaks under pressure.
Overtightening the adaptor	Threads, seals, ports or sealing faces can become damaged.
Choosing a straight adaptor where an elbow is needed	The hose may sit under strain, increasing the risk of leaks or failure.

Simple rule

If the adaptor does not seal correctly, do not keep tightening it. Check the thread type, seal, seat and mating component before applying more force.

8. Steel or Stainless Steel Hydraulic Adaptors?

Material choice matters when selecting a male to male hydraulic adaptor. Many hydraulic adaptors are made from steel with a protective finish, but stainless steel may be needed in more demanding environments.

Material	Typical use
Zinc-plated steel	Common choice for many general hydraulic systems, machinery, agriculture and industrial applications.
Stainless steel	Often used where corrosion resistance, washdown, harsh environments or specialist fluids are important.
Specialist materials	May be required for certain fluids, temperatures, pressures or industry-specific applications.

Always check that the adaptor material is suitable for the system pressure, hydraulic fluid, temperature and environment. The right thread is important, but the wrong material can still shorten service life or cause premature failure.

9. How to Measure a Male to Male Hydraulic Adaptor

If you are trying to identify an existing male to male adaptor, measuring both ends is the best place to start. Do not rely on guesswork or appearance alone.

Measure and check:

The outside diameter of the male thread
The thread pitch or threads per inch
Whether the thread is parallel or tapered
The sealing face, cone, washer, O-ring or seat
The overall length of the adaptor
The hex size, if space around the fitting is limited
Whether both ends are the same or different

A thread gauge and calipers can help identify the adaptor more accurately. You can also compare your measurements against Flowfit’s Hydraulic Fitting Thread Identification Guide.

Before ordering

Check both ends separately. Many male to male adaptors are conversion fittings, which means one end may be a different thread type or size from the other.

10. Replacement Checklist Before Ordering

Before ordering a replacement male to male hydraulic adaptor, work through a simple checklist. This helps reduce the risk of ordering a fitting that looks right but does not seal correctly.

Identify side one: thread type, size and sealing method.
Identify side two: thread type, size and sealing method.
Check whether the adaptor is straight, elbow, tee, reducing or bulkhead style.
Confirm the pressure rating is suitable for the hydraulic system.
Check the material is suitable for the environment and fluid.
Inspect the mating components for damaged threads or sealing faces.
Replace any worn bonded seals, washers or O-rings.

If you are replacing a leaking adaptor, the problem may not be the adaptor alone. The thread, seal, seat, port or hose alignment may also need to be checked.

Do not guess the thread

Guessing a hydraulic thread can lead to leaks, damaged components and repeat orders. Use measurements, thread identification tools or expert support if you are unsure.

11. Need Help Finding the Right Male to Male Hydraulic Adaptor?

Flowfit supplies a wide range of male to male hydraulic adaptors, including BSP, JIC, metric, reducing, straight, elbow, bulkhead and conversion fittings. Whether you are replacing a damaged adaptor or building a new hydraulic connection, choosing the right thread and sealing method is essential.

If you are unsure which adaptor you need, compare your old fitting carefully, use the thread identification guide, or read our full hydraulic adaptor selection guide before ordering.

Tip: A male to male hydraulic adaptor must match both female connections correctly. Always check the thread type, size and seal before fitting.