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.
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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. Aluminum-plated brass nuts have better corrosion and wear resistance than unplated brass.
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.
- Maximum Pressure: See table
- Maximum Temperature: 120° F, except DIN 477 No. 9: 250° F
| Number | Thread Size  | Thread Type | Thread Direction | Max. Pressure | For Use With | Each | |
Aluminum-Plated Brass | |||||||
|---|---|---|---|---|---|---|---|
| DIN 477 No. 6 | W 21.8 | Metric | Right Hand | 3,000 psi @ 72° F | Argon, Carbon Dioxide, Cyclobutane, Dichlorotetrafluoroethane, Helium, Krypton, Sulfur Hexafluoride, Trifluoroethane, Xenon | 000000000 | 000000 |
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 has a rounded end that sits 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.
For technical drawings and 3-D models, click on a part number.
- 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 | ||||||
| DIN 477 No. 6 (4,350 psi @ 72° F) | 1/4 | NPT | 3 1/2" | Argon, Carbon Dioxide, Cyclobutane, Dichlorotetrafluoroethane, Helium, Krypton, Sulfur Hexafluoride, Trifluoroethane, Xenon | 000000000 | 000000 |
- Maximum Pressure: See table
- Maximum Temperature: 120° F
| Number | Gender | Thread Size | Thread Type | Thread Direction | Max. Pressure | For Use With | Each | |
Aluminum-Plated Brass | ||||||||
|---|---|---|---|---|---|---|---|---|
| DIN 477 No. 6 | Female | W 21.8 | Metric | Right Hand | 3,000 psi @ 72° F | Argon, Carbon Dioxide, Cyclobutane, Dichlorotetrafluoroethane, Helium, Krypton, Sulfur Hexafluoride, Trifluoroethane, Xenon | 000000000 | 000000 |