How to Use a Gaugeable Preswaging Tool

For Swagelok tube fitting installations in tight, compact spaces, the Swagelok gaugeable preswaging tool can be a convenient accessory to help you make reliable connections.

Before beginning the tube fitting installation process, be sure you have the right tools available. You will need the gaugeable preswaging tool in the appropriate fractional or metric size—fractional tools have a blue band, while metric tools have a yellow band. You will also need tubing that meets minimum wall‑thickness recommendations, a Swagelok tube fitting with a nut and both front and back ferrules, appropriate wrenches, and a standard Swagelok gap gauge.

To begin, place the preswaging tool into a vise and remove the nut from the tool. Install the fitting nut and ferrules onto the preswaging tool, ensuring the ferrules are oriented correctly. Insert the tube into the preswaging tool until it bottoms out on the internal shoulder, then rotate the nut until finger‑tight.

While holding the preswaging tool steady, tighten the nut with a wrench until it stops against the collar. Loosen the nut and remove the tube with the preswaged ferrules. If the tube sticks, gently rock it back and forth—do not turn the tube. Remove the preswaging tool from the vise.

Now you are ready to install the tube fitting. Insert the tube with the preswaged ferrules into the fitting until the front ferrule seats against the fitting body. Rotate the nut finger‑tight, then mark the nut at the six‑o’clock position. While holding the fitting body steady in a vise, tighten the nut one‑half turn to the twelve‑o’clock position.

If assembling fittings for high‑pressure applications or high safety‑factor systems (severe service), tighten one additional hex flat beyond the one‑half‑turn requirement. If a vise is not available, you may use a second open‑end wrench to hold the fitting body steady.

Use your Swagelok gap inspection gauge to confirm that the fitting has been sufficiently tightened. Position the gauge next to the gap between the nut and the body. If the gauge will not enter the gap, the fitting is properly tightened. If it will enter, additional tightening is required.

Now that you’ve learned how to use a Swagelok preswaging tool, you’ll be better equipped to make safe and reliable tube‑fitting connections. If you’re interested in learning more about best practices for tube‑fitting installation, Swagelok offers a wide variety of fluid and sampling system training opportunities.

For more information about Swagelok training, visit Swagelok.com and get in touch with our training specialists.