CGA 540 Fittings | McMaster-Carr

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8 Products

About Pipe and Fittings

Measure your pipe and fittings to identify their pipe size, thread size, schedule, and thread type. Then, find compatible components.

Nuts for High-Pressure Nipples for Compressed Gas

Slide a high-pressure hose nipple for compressed gas into one of these nuts to connect a pipe to the inlet of a pressure regulator. They are also known as CGA (Compressed Gas Association) nuts and inlet nuts.

Brass nuts have good corrosion resistance and are softer than 316 stainless steel nuts, so they're easier to thread together. Chrome-plated brass nuts have comparable corrosion and wear resistance to aluminum-plated brass nuts, and have a bright, shiny appearance.

Nuts with a plastic grip can be tightened by hand instead of with a wrench.

Note: Nuts have a CGA, BS, or DIN number that corresponds to a specific type of gas. Choose a nut with the same number as your tank and other system components.

Female

Female Nut

Maximum Pressure: See table
Maximum Temperature: 120° F, except DIN 477 No. 9: 250° F

Brass
Number	Thread Size	Thread Type	Thread Direction	Max. Pressure	For Use With		Each
CGA 540	0.908"-14	NGO	Right Hand	3,000 psi @ 72° F	Oxygen	79215A662	00000
Brass with Plastic Grip
CGA 540	0.908"-14	NGO	Right Hand	3,000 psi @ 72° F	Oxygen	79215A432	00000
Chrome-Plated Brass
CGA 540	0.908"-14	NGO	Right Hand	3,000 psi @ 72° F	Oxygen	79215A322	00000

High-Pressure Nipples for Compressed Gas

Commonly used in high-pressure welding applications, these nipples connect your tank to the inlet of a pressure regulator. One side has a threaded pipe end and the other side is designed to sit inside a threaded nut (sold separately) so you can make a threaded connection.

Brass nipples have good corrosion resistance and are softer than 316 stainless steel nipples, so they're easier to thread together. Chrome-plated brass nipples have better corrosion and wear resistance than unplated brass nipples and have a bright, shiny appearance.

Nipples, Tank × Male Regulator

Maximum Pressure: See table
Maximum Temperature: 120° F

	Regulator Connection
For Number (Max. Pressure)	Pipe Size	Thread Type	Lg.	For Use With		Each
Brass—Tighten With Wrench
CGA 540 (3,000 psi @ 72° F)	1/4	NPT	2 1/16"	Oxygen	79215A663	00000
Chrome-Plated Brass—Tighten With Wrench
CGA 540 (3,000 psi @ 72° F)	1/4	NPT	2 1/16"	Oxygen	79215A323	00000

Nuts

Female Nut

Maximum Pressure: See table
Maximum Temperature: 120° F

Brass
Number	Gender	Thread Size	Thread Type	Thread Direction	Max. Pressure	For Use With		Each
CGA 540	Female	0.908"-14	NGO	Right Hand	3,000 psi @ 72° F	Oxygen	79215A662	00000
Chrome-Plated Brass
CGA 540	Female	0.908"-14	NGO	Right Hand	3,000 psi @ 72° F	Oxygen	79215A322	00000

High-Pressure Threaded Fittings for Compressed Gas

Designed to handle high-pressure welding applications, these fittings are commonly used to connect pressure regulators to compressed gas tanks or cylinders. Fittings are also known as CGA (Compressed Gas Association) fittings. They are brass for good corrosion resistance.

Note: Fittings have a CGA number that corresponds to a specific type of gas. Choose a fitting with the same CGA number as your tank and other system components.

Female Tank × Female Regulator

Maximum Pressure: See table
Maximum Temperature: 120° F

CGA Number		Tank Connection			Regulator Connection
Tank	Regulator	Thread Size	Thread Type	Thread Direction	Thread Size	Thread Type	Thread Direction	Max. Pressure	For Use With		Each
Brass
540	580	0.908"-14	NGO	Right Hand	0.960"-14	NGO	Right Hand	3,000 psi @ 72° F	Argon, Helium, Krypton, Neon, Nitrogen, Oxygen, Xenon	7923A29	000000

Female Tank × Male Regulator

Maximum Pressure: See table
Maximum Temperature: 120° F

CGA Number		Tank Connection			Regulator Connection
Tank	Regulator	Thread Size	Thread Type	Thread Direction	Thread Size	Thread Type	Thread Direction	Max. Pressure	For Use With		Each
Brass
346	540	0.830"-14	NGO	Right Hand	0.908"-14	NGO	Right Hand	3,000 psi @ 72° F	Air, Oxygen	7923A18	000000

Male Tank × Male Regulator

Maximum Pressure: See table
Maximum Temperature: 120° F

CGA Number		Tank Connection			Regulator Connection
Tank	Regulator	Thread Size	Thread Type	Thread Direction	Thread Size	Thread Type	Thread Direction	Max. Pressure	For Use With		Each
Brass
580	540	0.960"-14	NGO	Right Hand	0.908"-14	NGO	Right Hand	3,000 psi @ 72° F	Argon, Helium, Krypton, Neon, Nitrogen, Oxygen, Xenon	7923A34	000000