NGO Nuts | McMaster-Carr

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37 Products

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.

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. 316 stainless steel nuts have excellent corrosion resistance.

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

Nuts with left-hand threads are identified with a notch.

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.

For technical drawings and 3-D models, click on a part number.

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 200	0.628"-20	NGO	Right Hand	500 psi @ 72° F	Acetylene	000000000	00000
CGA 280	0.750"-14	NGO	Right Hand	3,000 psi @ 72° F	Medical Gas Mixtures	000000000	00000
CGA 300	0.830"-14	NGO	Right Hand	500 psi @ 72° F	Ethyl Chloride	000000000	0000
CGA 320	0.830"-14	NGO	Right Hand	3,000 psi @ 72° F	Carbon Dioxide	000000000	0000
CGA 326	0.830"-14	NGO	Right Hand	3,000 psi @ 72° F	Nitrous Oxide	000000000	0000
CGA 330	0.830"-14	NGO	Left Hand	3,000 psi @ 72° F	Boron Trifluoride, Carbonyl Sulfide, Hydrogen Bromide, Hydrogen Chloride, Hydrogen Iodide, Hydrogen Sulfide, Methyl Bromide, Silicon Tetrafluoride, Sulfur Tetrafluoride	000000000	00000
CGA 346	0.830"-14	NGO	Right Hand	3,000 psi @ 72° F	Air	000000000	0000
CGA 347	0.830"-14	NGO	Right Hand	4,700 psi @ 72° F	Air	000000000	00000
CGA 350	0.830"-14	NGO	Left Hand	3,000 psi @ 72° F	Carbon Monoxide, Ethane, Ethylene, Hydrogen, Methane, Methyl Fluoride, Natural Gas	000000000	0000
CGA 410	0.855"-14	NGO	Left Hand	500 psi @ 72° F	Acetylene	000000000	0000
CGA 520	0.899"-14	NGO	Right Hand	500 psi @ 72° F	Acetylene	000000000	0000
CGA 540	0.908"-14	NGO	Right Hand	3,000 psi @ 72° F	Oxygen	000000000	0000
CGA 555	0.908"-14	NGO	Left Hand	3,000 psi @ 72° F	Butane, LP Gas	000000000	0000
CGA 577	0.965"-14	NGO	Right Hand	3,500 psi @ 72° F	Oxygen	000000000	00000
CGA 660	1.035"-14	NGO	Right Hand	3,000 psi @ 72° F	Refrigerant Gases	000000000	00000
CGA 701	1.108"-14	NGO	Right Hand	4,700 psi @ 72° F	Oxygen	000000000	00000
Brass with Plastic Grip
CGA 320	0.830"-14	NGO	Right Hand	3,000 psi @ 72° F	Carbon Dioxide	000000000	00000
CGA 346	0.830"-14	NGO	Right Hand	3,000 psi @ 72° F	Air	000000000	00000
CGA 540	0.908"-14	NGO	Right Hand	3,000 psi @ 72° F	Oxygen	000000000	00000
Chrome-Plated Brass
CGA 320	0.830"-14	NGO	Right Hand	3,000 psi @ 72° F	Carbon Dioxide	000000000	00000
CGA 326	0.830"-14	NGO	Right Hand	3,000 psi @ 72° F	Nitrous Oxide	00000000	00000
CGA 350	0.830"-14	NGO	Left Hand	3,000 psi @ 72° F	Carbon Monoxide, Ethane, Ethylene, Hydrogen, Methane, Methyl Fluoride, Natural Gas	000000000	00000
CGA 540	0.908"-14	NGO	Right Hand	3,000 psi @ 72° F	Oxygen	000000000	00000
316 Stainless Steel
CGA 670	1.035"-14	NGO	Left Hand	3,000 psi @ 72° F	Hydrogen Fluoride, Nitrogen Trifluoride, Tungsten Hexafluoride	000000000	00000
CGA 677	1.035"-14	NGO	Left Hand	6,400 psi @ 72° F	Argon, Helium, Krypton, Neon, Nitrogen, Xenon	000000000	00000

Male

Male Nut

Maximum Pressure: See table
Maximum Temperature: 120° F, except DIN 477 No. 12: 250° F

Brass
Number	Thread Size	Thread Type	Thread Direction	Max. Pressure	For Use With		Each
CGA 500	0.880"-14	NGO	Right Hand	3,000 psi @ 72° F	Medical Gas Mixtures	000000000	000000
CGA 510	0.880"-14	NGO	Left Hand	500 psi @ 72° F	Acetylene, Butane, Cyclopropane, Dimethyl Ether, Ethylene Oxide, Isobutane, Methane, Methyl Chloride, Natural Gas, Propane, Propylene, Vinyl Bromide, Vinyl Chloride	000000000	0000
CGA 580	0.960"-14	NGO	Right Hand	3,000 psi @ 72° F	Argon, Helium, Krypton, Neon, Nitrogen, Xenon	000000000	0000
CGA 590	0.960"-14	NGO	Left Hand	3,000 psi @ 72° F	Sulfur Hexafluoride	000000000	0000
CGA 680	1.040"-14	NGO	Right Hand	4,700 psi @ 72° F	Argon, Helium, Krypton, Neon, Nitrogen, Xenon	000000000	00000
CGA 702	1.120"-14	NGO	Right Hand	6,400 psi @ 72° F	Air	000000000	00000
Brass with Plastic Grip
CGA 500	0.880"-14	NGO	Right Hand	3,000 psi @ 72° F	Medical Gas Mixtures	00000000	00000
CGA 510	0.880"-14	NGO	Left Hand	500 psi @ 72° F	Acetylene, Butane, Cyclopropane, Dimethyl Ether, Ethylene Oxide, Isobutane, Methane, Methyl Chloride, Natural Gas, Propane, Propylene, Vinyl Bromide, Vinyl Chloride	000000000	00000
CGA 580	0.960"-14	NGO	Right Hand	3,000 psi @ 72° F	Argon, Helium, Krypton, Neon, Nitrogen, Xenon	000000000	00000
Chrome-Plated Brass
CGA 510	0.880"-14	NGO	Left Hand	500 psi @ 72° F	Acetylene, Butane, Cyclopropane, Dimethyl Ether, Ethylene Oxide, Isobutane, Methane, Methyl Chloride, Natural Gas, Propane, Propylene, Vinyl Bromide, Vinyl Chloride	000000000	00000
CGA 580	0.960"-14	NGO	Right Hand	3,000 psi @ 72° F	Argon, Helium, Krypton, Neon, Nitrogen, Xenon	000000000	00000
CGA 590	0.960"-14	NGO	Left Hand	3,000 psi @ 72° F	Sulfur Hexafluoride	000000000	00000