Why Do Rivet Nuts Perform So Well in Round Tubes?

Rivet nuts are a popular way to add strong threads into thin metal. Install access is only needed on one side of the application while the installation occurs on the other side of material, which is often called the blind side. The newly installed threads in the parent application allow secondary attachments to be added and removed. One may think rivet nuts wouldn’t work in a round tube, but in most cases, rivet nuts and round tubing are an ideal application together.

In flat sheet metal, a rivet nut holds in place mostly because of how it upsets or bulges on the back side and the friction against the surface created by the installation. This is typical of how most fasteners create retaining strength.

Round tubes can give rivet nuts an extra advantage. When the rivet nut is installed, the curved wall of the tube wraps slightly along the curvature of the inside wall of the tubing. This helps reduce spin-out failures and can help increase other engineering values, subject confirmation via to a lab or field test. As you can see from the examples in the photos below, both the round and hex rivet nuts work well in round tubes.

              

Using a hex-shaped rivet nut or HEX NUT® can be even more beneficial. The flat sides of the hex shape can grip the tube wall better, which help resist spin-out rotation even more so. Because of these advantages, rivet nuts are often used in things like frames, racks, enclosures, and other tubing structures for applications in industries such as electronics, automotive, heavy truck, after-market accessories, agriculture, and aerospace. They can also be a good alternative to welding nuts onto tubing, since rivet nuts avoid heat distortion of the parent material while eliminating risk of a poor weld. For more information on Rivet Nuts, read our article on why you should use rivets nuts!

When installed properly, rivet nuts in tubes tend to sit straight, form a solid backside, and keep their threads usable. Still, like any fastener, they need the right size hole, correct installation, and proper use to perform well. Read our article for more information on how to properly install a rivet nut and why this is so important!

Round tubes help rivet nuts grip better and distribute force, which can make the connection stronger and more reliable. Rivet Nut USA™, a division of Cardinal Components, Inc., stocks a wide variety of rivet nuts, hex nuts, plus nuts, specialty fasteners, and installation tooling. To get more information or a quote on our full line of products, contact us to speak with one of our fastener experts!