Hydraulic Plugs | McMaster-Carr

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How to Identify and Measure Fittings

Pipe size is an industry designation, not the actual size. View information about how to measure threaded and unthreaded pipe and pipe fittings.

Compact Extreme-Pressure
Steel Threaded Pipe Fittings

These fittings are strong enough to handle extreme pressures, yet small enough to fit into cramped spaces.

Compact Precision Extreme-Pressure
Steel Threaded Pipe Fittings

Made to tighter tolerances than other steel pipe fittings, these are also known as instrumentation fittings.

Extreme-Pressure Steel Threaded Pipe Fittings

The strongest steel fittings we offer, these can withstand extreme-pressure applications.

High-Pressure Galvanized Steel Threaded Pipe Fittings

A galvanized finish gives these fittings better corrosion resistance than our plain steel high-pressure fittings. Also known as Pressure Class 3000 fittings.

High-Pressure Iron and Steel Threaded Pipe Fittings

These fittings can stand up to high-pressure applications. Use them in noncorrosive environments.

Extreme-Pressure Socket-Connect
Steel Unthreaded Pipe Fittings

Also known as Pressure Class 6000 fittings, these heavy duty forged fittings are the strongest steel fittings we offer.

Extreme-Pressure Stainless
Steel Threaded Pipe Fittings

Use these fittings in extreme-pressure conditions up to 15,000 psi.

Precision Extreme-Pressure Stainless
Steel Threaded Pipe Fittings

These fittings are made to tighter tolerances than other stainless steel pipe fittings. They are also known as instrumentation fittings.

High-Pressure Stainless Steel Threaded Pipe Fittings

Use these heavy duty, corrosion-resistant fittings in high-pressure flow applications.

High-Pressure Socket-Connect
Stainless Steel Unthreaded Pipe Fittings

Socket-connect fittings are easier to weld than butt-weld fittings because the fitting doesn't need to align perfectly to the pipe. Slip the pipe into the socket and weld.

Low-Pressure Aluminum Threaded Pipe Fittings

In addition to being lightweight, these aluminum fittings offer good corrosion resistance. Use them in low-pressure flow applications.

Medium-Pressure Aluminum Threaded Pipe Fittings

Designed for medium-pressure applications, these fittings have better strength than our low-pressure aluminum pipe fittings.

Low-Pressure Plated Brass Threaded Pipe Fittings

Used in low-pressure pipe lines, these brass fittings have a plating that makes them shiny and improves corrosion resistance.

Tube Fittings for Metal Tubing

Precision AN 37° Flared Fittings
for Stainless Steel Tubing

The threads on the tube end of these fittings are Class 3A or 3B and adhere to tighter tolerances than other 37° flared fittings.

Vibration-Resistant Precision AN 37°
Flared Fittings for Stainless Steel Tubing

A PTFE seal on the tube end of these fittings allows for an extra-strong connection in high-vibration applications.

37° Flared Fittings for Stainless Steel Tubing

Also known as JIC (Joint Industrial Council) fittings, these provide a tight metal-to-metal seal on stainless steel tubing that is flared to 37°.

Precision Compression Fittings
for Stainless Steel Tubing

Compression Fittings for Stainless Steel Tubing

A single sleeve (ferrule) bites into tubing as you tighten the nut, creating a strong seal. The nut and sleeve are included.

Yor-Lok Fittings for Stainless Steel Tubing

Use these fittings at pressures up to 9,700 psi. Also known as instrumentation fittings, they are made to tight tolerances for use in high-precision applications. They are compatible with Swagelok®, Let-Lok, and Parker A-Lok fittings.

37° Flared Fittings for Steel Tubing

Also known as JIC (Joint Industrial Council) fittings, these provide a tight metal-to-metal seal on steel tubing that is flared to 37°.

30° Flared Fittings for Steel Tubing

Also known as JIS (Japanese Industrial Standard) fittings.

High-Pressure Compression Fittings for Steel Tubing

Thicker walls make these fittings—sometimes called flareless or bite fittings—withstand about twice as much pressure as standard compression fittings, so they’re good for hydraulic power applications.

Compression Fittings for Steel Tubing

A single sleeve (ferrule) bites into tubing as you tighten the nut, creating a strong seal.

Yor-Lok Fittings for Steel Tubing

These fittings have two sleeves for extra gripping power. They bite into steel tubing as you tighten the nut to form a strong seal.

37° Flared Fittings for Aluminum Tubing

Also known as JIC (Joint Industrial Council) fittings, these provide a tight seal on tubing that is flared to 37°.

Yor-Lok Fittings for Copper Tubing

Precision Compression Fittings for Copper Tubing

Also known as instrumentation fittings, these are made to tighter tolerances than standard compression fittings. They are compatible with Parker CPI fittings.