NPSM Female Pipe Swivel Fittings (Carbon Steel) | Wholesale & OEM Supply

Where NPSM Swivels Sit in a Hydraulic Fitting System

NPSM is not a general-purpose port. It is a very specific tool: a straight-thread female swivel that lets you point a hose end wherever you want while the seal happens on a tapered male thread. In real hydraulic systems it normally works alongside other standards, not instead of them.

• NPSM + NPT/NPTF: every part in the catalog above is designed to land on a male tapered thread. Match the NPSM swivel with our NPT/NPTF pipe fittings when you want hose ends that install cleanly on existing pipe ports.
• When NPT starts leaking: if vibration or pressure makes NPT seals unreliable, keep the swivel function on the hose end but move the port over to SAE ORB or ORFS for a true engineered O-ring seal.
• NPSM vs JIC hose ends: on many hose assemblies you can choose between an NPSM swivel or a JIC female swivel. NPSM is better when you must land on tapered pipe threads; JIC is better when you can control both sides of the connection and prefer a metal seal with no sealant.
• NPSM on imported BSPP/BSPT equipment: do not thread NPSM directly onto British threads. First adapt the port using BSPP or BSPT fittings, then land the hose with an NPSM swivel on an NPT/NPTF male adapter.
• When corrosion is the real enemy: mirror critical hose ends in our stainless NPSM swivels and pair them with stainless NPTF pipe fittings in marine or chemical areas, while keeping the rest of the system in carbon steel.

Toolbox Talk: The NPSM Swivel

This fitting is a simple lifesaver, but it's important to know exactly how it works and where it fits in. It’s not the same as a standard NPT female port.

How it Works: Straight Threads for Strength, Swivel for Sanity

Think of it like a nut and bolt, not a wedge. Here’s the breakdown:

• The Threads are Straight: NPSM threads are parallel. They don't create a seal by themselves. Their only job is to provide the clamping force to pull the connection tight.
• The Swivel Does the Work: The nut spins freely from the body of the fitting. This is the whole point. It lets you tighten the connection while holding the fitting body (and the hose) perfectly still.
• The Seal Happens Elsewhere: The NPSM swivel itself doesn't seal. When you thread it onto a common male NPT (tapered) fitting, the seal is made on those male tapered threads as they wedge into the seat at the bottom of the swivel. The NPSM nut just provides the force.

The Big Win: Why You'll Be Glad You Used a Swivel

• No Hose Twist. Period. You can stop damaging expensive hose assemblies during installation.
• Perfect Alignment: Get your elbows and tees pointed exactly where you want them without having to back-off a tight connection (which always causes leaks).
• Easier to Wrench in Tight Spots: When you can’t get a wrench on the fitting body, just being able to spin the nut makes a tough job easy.

The Trade-Offs: Know Its Limits

Because this system relies on a basic NPT-style tapered thread seal, it has the same limits as NPT. It's fantastic for most standard hydraulic applications, but for extreme high-pressure or heavy vibration, you should step up to an engineered seal like ORB or ORFS. This fitting is a clever mechanical solution, not a high-performance seal in and of itself.

How to Install it Right (No Shortcuts)

1. Clean Both Sets of Threads. Get the dirt and old pipe dope out of there.
2. Apply Sealant to the MALE Tapered Threads ONLY. Never put tape or paste inside the female swivel. You'll just flush it into your pump.
3. Thread it on by hand. Make sure it spins on smooth and easy before you put a wrench on it.
4. Use TWO Wrenches. Always. One wrench holds your elbow or tee perfectly still. The other tightens the swivel nut.
5. Get it good and snug. You're tightening to seal the male NPT threads, so give it the standard 1.5 to 3 turns past hand-tight. You’ll feel it seat.

Straight Answers to Common NPSM Questions