This Swagelok® union is used to connect 1/4 in. tubing and is made of 316 stainless steel. Unions include nuts and ferrule sets. Nut threads are silver plated to prevent galling and seizing of the fitting when tightened.

Unions are used when two same-size bare tubing ends need to be joined. Unions are made with the nuts facing each other. Reducing Unions are used when it is necessary to join two different bare tubing sizes. A single reducing union can take the place of many fittings and requires less space.

These industry standard Swagelok compression-type fittings and components are precision manufactured and offer a gas-tight, metal-on-metal seal. They are available in standard fractional tubing sizes for making up stainless steel tubing. Polished surface finishes and high purity materials virtually eliminate these fittings as a source of system contamination.

They can be used for any fluid flow application and provide leak-tight service from vacuum to positive pressure. These fittings offer consistent gaugeability upon initial installation and are easy to disconnect and retighten reliably.

The two-ferrule design of these fittings are easy to install and no torque is transmitted to the tubing during installation. The two ferrules separate sealing and tube gripping functions; each ferrule is optimized for its function. Available Swagelok gap inspection gauges assure sufficient pull-up upon initial installation.

Swagelok tube fitting ends are rated to the working pressure of tubing as listed in the Swagelok Tubing Data PDF, available here for download.

Fitting specifications are shown in the second image.