A variety of forged steel BSPP hydraulic fittings on a factory table, highlighting the parallel G-threads and shoulders designed for use with bonded seals.

BSPP (G Thread) Pipe Fittings – Steel

The Standard Fitting for Most Equipment Built Outside North America.

It's a G Thread. Here's How It Works.

If you're working on equipment from just about anywhere outside of the US or Canada, you're going to run into a BSPP fitting. It stands for British Standard Pipe Parallel, and it's also called a "G" thread. The most important thing to know is that it is NOT a tapered thread like an NPT. The threads are straight, or parallel. That means the threads themselves do NOT create the seal.

So how does it seal? Simple. A BSPP connection relies on a separate seal that gets compressed between a shoulder on the male fitting and a flat face on the female port. Most of the time, that's a bonded seal (some people call it a Dowty washer). The threads just provide the clamping force to squeeze that seal tight. It's a simple, robust system, and we manufacture a full line of steel adapters to help you connect your equipment right.

BSPP Fitting & Adapter Catalog (Steel)

ORFS Male to BSPP Male Adapter (Eolastic Seal)

ORFS Male x BSPP Male Adapter (ES Seal)

Part #: 6002

Straight adapter connecting a female ORFS swivel to a female BSPP port. Male ORFS x Male BSPP (designed for sealing with Eolastic/Bonded Seal).

ORFS Male to BSPP Male Adapter Long (ES Seal)

ORFS Male x BSPP Male Adapter Long (ES Seal)

Part #: 6002L

Long version of the 6002 adapter (Male ORFS x Male BSPP with ES seal face) for extended reach.

ORFS Male to BSPP Male 45° Elbow (ES Seal)

ORFS Male x BSPP Male 45° Elbow (ES Seal)

Part #: 6058

45° adapter elbow connecting a female ORFS swivel to a female BSPP port. Male ORFS x Male BSPP (ES seal) ends.

ORFS Male to BSPP Male 90° Elbow (ES Seal)

ORFS Male x BSPP Male 90° Elbow (ES Seal)

Part #: 6059

90° adapter elbow connecting a female ORFS swivel to a female BSPP port. Male ORFS x Male BSPP (ES seal) ends.

BSPP Male Nipple / Union

Part #: 9000

Straight connector (union) with male BSPP threads on both ends for joining two female BSPP ports.

JIC Male x BSPP Male Adapter (ES Seal)

Part #: 9002

Straight adapter connecting a female JIC swivel/tube to a female BSPP port. Male JIC x Male BSPP (ES seal) ends.

JIC Male to BSPP Male Long Adapter (ES Seal)

JIC Male x BSPP Male Long Adapter (ES Seal)

Part #: 9002L

Long version of the 9002 adapter (Male JIC x Male BSPP with ES seal face).

JIC Male x BSPP Male Adapter

Part #: 9005

Straight adapter connecting a female JIC swivel/tube to a female BSPP port. Male JIC x Male BSPP ends (likely requires bonded seal).

SAE ORB Male x BSPP Male Adapter

Part #: 9006

Straight adapter connecting a female SAE ORB port to a female BSPP port. Male ORB x Male BSPP ends (requires bonded seal).

BSPP Male x NPTF Pipe Male Adapter

Part #: 9007

Straight adapter connecting a female BSPP port (using bonded seal) to a female NPTF port (seal on threads).

BSPP Male x Female BSPP Swivel Adapter

Part #: 9015

Straight adapter connecting a male BSPP fitting to a female BSPP port, featuring a swivel nut for alignment.

BSPP Test Port Tee

Part #: 9015TP

Tee fitting with BSPP connections, incorporating a dedicated test port (often M16x2 or similar) for pressure checking.

BSPP Male x Female JIC Swivel Adapter

Part #: 9021

Straight adapter connecting a male JIC flare fitting/tube to a female BSPP port (using bonded seal).

NPTF Male Pipe x Female BSPP Swivel Adapter

Part #: 9023

Straight adapter connecting a male NPTF pipe/fitting to a male BSPP fitting (seal on NPTF threads).

Female BSPP Swivel x Female BSPP Swivel Union

Part #: 9025

Straight union connecting two male BSPP fittings using female BSPP swivel nuts on both ends.

Female BSPP Swivel x Female JIC Swivel Adapter

Part #: 9027

Straight adapter connecting a male BSPP fitting to a male JIC fitting.

BSPP Plug (Hollow Hex Socket)

Part #: 9028

Seals a female BSPP port. Male BSPP thread with an internal hex drive. Requires bonded seal or similar.

BSPP Plug (Solid Hex Head)

Part #: 9030

Seals a female BSPP port. Male BSPP thread with external hex head. Requires bonded seal or similar.

BSPP Cap

Part #: 9033

Seals the end of a male BSPP threaded fitting. Female BSPP thread, usually with internal seal face or requires gasket.

BSPP Male x Female NPTF Pipe Adapter

Part #: 9035 / 9035S

Straight adapter connecting a male NPTF pipe/fitting into a female BSPP port (using bonded seal).

BSPP Male x Female ORB Adapter

Part #: 9036

Straight adapter connecting a male SAE ORB fitting into a female BSPP port (using bonded seal).

NPTF Male Pipe x Female BSPP Adapter

Part #: 9037

Straight adapter connecting a male BSPP fitting into a female NPTF port (seal on male threads).

BSPP Male x Female BSPP Bushing / Reducer

Part #: 9038 / 9039

Reducer bushing connecting different BSPP thread sizes. Male BSPP external, smaller Female BSPP internal.

BSPP Male x BSPP Male Bulkhead Union

Part #: 9040 / 9040L

Connects two female BSPP swivel fittings/hoses through a panel or bulkhead. Straight union with locknut.

Female BSPP x Female BSPP Union/Coupling

Part #: 9043

Straight union connecting two male BSPP fittings. Female BSPP threads both ends.

BSPP Male to Female BSPP Swivel 90° Elbow

BSPP Male x Female BSPP Swivel 90° Elbow

Part #: 9045 / 9060

90° elbow connecting a male BSPP fitting to a female BSPP port, featuring a swivel nut for easy alignment.

BSPP Male to Female BSPP Swivel 45° Elbow

BSPP Male x Female BSPP Swivel 45° Elbow

Part #: 9047 / 9048 / 9053?

45° elbow connecting a male BSPP fitting to a female BSPP port, featuring a swivel nut for easy alignment.

Female BSPP Swivel to Female BSPP Swivel 90° Elbow

Female BSPP Swivel x Female BSPP Swivel 90° Elbow

Part #: 9050

90° elbow connecting two male BSPP fittings using female BSPP swivel nuts on both ends.

BSPP Male x BSPP Male 45° Elbow

Part #: 9051

45° elbow connecting two female BSPP ports. Male BSPP threads on both ends.

BSPP Male x BSPP Male 90° Elbow

Part #: 9052 / 9055

90° elbow connecting two female BSPP ports. Male BSPP threads on both ends.

JIC Male to Female BSPP Swivel 90° Elbow

JIC Male x Female BSPP Swivel 90° Elbow

Part #: 9056

90° adapter elbow connecting a male JIC flare fitting/tube to a male BSPP fitting.

BSPP Male x BSPT Male 90° Elbow

Part #: 9057

90° adapter elbow connecting a female BSPP port (using bonded seal) to a female BSPT port (seal on threads).

JIC Male x BSPP Male 45° Elbow

Part #: 9058

45° adapter elbow connecting a female JIC swivel/tube to a female BSPP port.

JIC Male x BSPP Male 90° Elbow

Part #: 9059 / 9059L / 9065?

90° adapter elbow connecting a female JIC swivel/tube to a female BSPP port. (Standard/Long versions may exist).

BSPP Male to Female JIC Swivel 90° Elbow

BSPP Male x Female JIC Swivel 90° Elbow

Part #: 9061

90° adapter elbow connecting a male JIC flare fitting/tube to a female BSPP port (using bonded seal).

BSPP Male x NPTF Male 90° Elbow

Part #: 9070

90° adapter elbow connecting a female BSPP port (using bonded seal) to a female NPTF port (seal on threads).

Related BSPP Accessories

Bonded O-Ring Seal (Buna-N)

Part #: 9500 Series

Standard Buna-N (Nitrile) bonded seal (Dowty washer) used for sealing male BSPP fittings against flat surfaces.

Viton® Bonded O-Ring Seal

Part #: 9500V Series

Viton® (FKM) bonded seal for BSPP fittings, offering enhanced chemical and temperature resistance.

BSPP Bulkhead Locknut

Part #: 9041

Nut used to secure a BSPP bulkhead fitting (like 9040 series) to a panel or bulkhead wall.

The Shop Floor Truth on BSPP (G Threads)

A lot of mechanics get tripped up by BSP threads because they look a little like our NPT. They are not the same. Using the wrong one will cause a bad leak and probably wreck the threads. Here's the no-nonsense guide to getting it right.

How It Seals: A Gasket, Not a Wedge

An NPT thread seals by wedging itself into the port. A BSPP fitting works more like the head gasket on an engine. Here’s the setup:

Parallel Threads: The male and female threads are straight. Their only job is to pull the fitting into the port and hold it there.
The Bonded Seal: This is the key. It's a metal washer with a rubber ring bonded to the inside. You slip it over the male threads, and it sits against a shoulder on the fitting.
The Flat Face: The female port needs to have a smooth, flat surface around the hole. When you tighten the fitting, it squashes that rubber ring between the fitting's shoulder and the port's flat face. That's your seal.

Key Differences from NPT (What You Need to Know)

Thread Angle: BSP threads have a 55-degree angle. NPT threads are 60 degrees. They won't mate correctly.
Thread Pitch: The spacing of the threads is different for most sizes.
The Seal: BSPP uses a seal. NPT uses the threads themselves.

The bottom line: Don't ever try to force an NPT fitting into a BSPP port, or vice versa. You'll ruin both parts.

Why It's a Good System

Reliable Seal: That bonded seal creates a very solid, reliable connection that holds up well against vibration.
Reusable: Since you're not deforming the threads, you can take the connection apart and put it back together. Just use a fresh bonded seal each time.
No Pipe Dope in Your System: You don't use thread sealant, so there's no risk of contaminating your hydraulic fluid with Teflon tape or paste.

How to Install it Right

Clean Everything. The male threads, the shoulder on the fitting, and especially the flat face on the port have to be spotless.
Use a New Bonded Seal. Don't try to reuse the old one. It's not worth the risk. Slide it over the threads.
Thread it in by hand. Make sure it goes in smooth until the seal makes contact with the port face.
Wrench-tighten to spec. Use a torque wrench if you have the specs. You're not trying to stretch the bolt; you're just applying enough pressure to properly compress the bonded seal. You'll feel it seat firmly. Don't go crazy on it.

The Right Fittings for Your International Equipment.

As a global manufacturer, we keep a deep inventory of BSPP / G-thread adapters to help our North American partners service equipment from around the world. For wholesale pricing on the parts you need to get the job done, talk to our team.

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