3/8"-24 Couplings | McMaster-Carr

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260 Products

Hose Fittings

Metal Barbed Hose Fittings for Air and Water

Metal hose fittings have better durability than plastic barbed hose fittings.

Metal Barbed Hose Fittings
for Chemicals and Petroleum

These metal hose fittings have better durability than plastic barbed hose fittings. They are 316 stainless steel for excellent corrosion and chemical resistance. Slide the barbed end into hose and secure with a clamp.

Threaded Hose Fittings for Compressed Gas

Use these CGA fittings to connect welding hose to pressure regulators and torches.

Nuts for Barbed Hose Fittings for Compressed Gas

Also known as CGA nuts, these are designed for low-pressure welding applications downstream of your pressure regulator. Attach them to barbed hose fittings for compressed gas to make a threaded connection to torches or pressure regulators.

Couplers for High-Pressure Fill Valves

Tube Fittings for Metal Tubing

45° Flared Fittings for Copper and Brass Tubing

No sleeve is required to assemble these fittings, which makes for a faster, more convenient installation compared to 37° flared fittings. They are also known as refrigeration and SAE fittings.

Nuts for 45° Flared Fittings
for Copper and Brass Tubing

37° Flared Fittings for Copper Tubing

Also known as JIC (Joint Industrial Council) fittings, these connect to tubing that is flared to 37°. They can handle higher pressures than 45° flared fittings.

Nuts for 37° Flared Fittings for Copper Tubing

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°.

Nuts for 37° Flared Fittings
for Stainless Steel Tubing

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°.

Nuts for 37° Flared Fittings for Steel Tubing

Use these nuts with a sleeve and fitting to provide a tight metal-to-metal seal on steel tubing that is flared to 37°.

Nuts for 37° Flared Fittings for Aluminum Tubing

Tight-Space 37° Flared Fittings for Aluminum Tubing

The external hex bolt on these fittings allows for easy installation in cramped spaces. They are also known as banjo-style fittings and JIC (Joint Industrial Council) fittings. They provide a tight seal on tubing that is flared to 37°.

Coupling Nuts

Low-Strength Steel Coupling Nuts

About half the strength of medium-strength steel coupling nuts, these nuts are for light duty fastening applications.

Medium-Strength Steel Coupling Nuts—Grade 5

Made from Grade 5 steel, these inch-sized coupling nuts are suitable for most applications.

High-Strength Steel Coupling Nuts—Grade 8

Made from Grade 8 steel, these nuts are about 25% stronger than medium-strength steel coupling nuts. Furnished in inch thread sizes.

18-8 Stainless Steel Coupling Nuts

These coupling nuts have good chemical resistance.

Super-Corrosion-Resistant 316
Stainless Steel Coupling Nuts

More corrosion resistant than 18-8 stainless steel coupling nuts, these nuts have excellent resistance to chemicals and salt water.

Brass Coupling Nuts

Brass coupling nuts are corrosion resistant in wet environments and electrically conductive.

Stainless Steel Extra-Long Coupling Nuts

Stainless steel coupling nuts have excellent corrosion resistance in most environments.

Round Coupling Nuts

A smooth rounded body provides a finished look.

Coupling Nuts with Sight Hole

Use the sight hole to check for proper thread engagement.

Thread Adapters

Inch-to-Inch Male-Female Hex Thread Adapters

Change thread sizes or types, such as fine to coarse threads, on parts without changing gender.

Inch-to-Metric Male-Female Hex Thread Adapters

Change inch threads to metric with these adapters, or swap metric threads for inch. An external hex lets you tighten or loosen them with a wrench.

Inch-to-Inch Female Hex Thread Adapters

Connect two differently sized male-threaded parts, such as threaded rods, and tighten with a standard wrench.

Left-Hand to Right-Hand
Female Hex Thread Adapters

Often called sleeve nuts, these thread adapters fasten parts with right-hand threads to parts with left-hand threads.

Inch-to-Metric Female Hex Thread Adapters

Adapt threaded rods from inch to metric. These adapters connect two male-threaded fasteners, so you can change the gender of a mating part or increase or decrease its thread size. The hex-shaped body fits into the head of a standard wrench.

Inch-to-Inch Male Hex Thread Adapters

Need to join two female-threaded parts, such as coupling nuts, with dissimilar inch thread sizes? Attach them to these adapters and tighten the exterior hex nut for a secure connection.

Inch-to-Metric Male Hex Thread Adapters

One side inch, one side metric, and a hex in the middle—these handy fasteners connect two female-threaded parts, such as coupling nuts, adapting from inch threads to metric. Tighten with a standard wrench.

Rod Alignment Couplers

Increase cylinder life by fixing alignment problems between air or hydraulic cylinders and driven components.

Threaded Adapters for Pullers

Use adapters on the ends of forcing screws and face-grip puller legs when pulling shafts, bearing caps, and pinions.

Extension Spring Stud Anchors

Corrosion-Resistant Extension Spring Stud Anchors

These stainless steel anchor studs offer excellent corrosion resistance.