Category Archive: Rivet Nuts

Watertight Rivet Nuts

In an earlier post we talked about how corrosion should be considered when choosing the type of rivet nut to use in your next project, and what types of sprays can help deter or limit the pace of red rust and white rust from occurring.

Now water will certainly speed up the corrosion process, but that shouldn’t eliminate the use of rivet nuts in wet conditions, or conditions where a rivet nut will spend some of its life submerged in water or fluid.

Our partner Tubtara® has a few different watertight and fluid proof rivet nuts that are designed with seals underneath the flange to keep water and fluids from leaking through the rivet nut. Tubtara’s Watertight HX series feature a O-ring seal mounted underneath the flange, and provides protection against moisture, oil, and dirt under high pressures. Despite the O-ring, it will deliver a metal to metal contact after installation.

Tubtara Sherex Watertight HX

Tubtara Watertight HX Rivet Nut. Notice the O-ring seal underneath the flange.

The Watertight (H)DPX Series is a rivet nut that has an applied sealant underneath the head. This non-reactive seal is resistant to many auto oils, antifreeze and other kinds of fluids with a higher viscosity. The seal in the (H)DPX Series can come in a variety of different seal material including NBR, Viton, silicone, epoxy based, acrylate and polyurethane resin.

Tubtara Sherex HDPX Rivet Nuts

Non-reactive seal is great for use in high viscosity fluids

Any application where you wouldn’t want water or fluid to leak underneath or through the rivet nut should require a watertight rivet nut. Without using one of the seals, whether it’s an O-ring or sealant, it may not be completely watertight – especially as corrosion begins to develop.

For more information on watertight rivet nuts, or if looking for a solution for fasteners that will perform well under water or fluid, contact us!

Spin-Spin vs. Spin-Pull Rivet Nut Tooling

When it comes to rivet nut tooling, there are a variety of different options. While small-volume applications may often result in a manual hand tool being the best choice, larger-volume installation projects may require more robust tooling. Two of the most popular non-manual options are air-powered tools that install rivet nuts through either a spin-spin and spin-pull action.

Let’s go through the differences between spin-spin and spin-pull rivet nut installation tools.

Spin-Spin Rivet Nut Tool

A spin-spin rivet nut tool is an air-powered tool that, once a rivet nut is secured onto it, utilizes torque to spin its mandrel inward in order to collapse the rivet nut. The torque, driven by an air motor, ramps up continuously until the rivet nut fully collapses. After installation, the tool’s reverse trigger must be pressed to separate the tool from the now-installed rivet nut. In order to both maintain tool integrity as well as ensure proper installations, it is recommended that spin-spin mandrels be lubricated with wax.

The benefit of using spin-spin tools is that they are less expensive than spin-pull and can often be more lightweight, but its capabilities aren’t as complete as the spin-pull tool.

The installation base material can vary in thickness, but it is recommended that the rivet nuts being installed are thin-walled steel, aluminum or brass. Also, depending on what kind of spin-spin tool you purchase, it may often be limited in the thread sizes it can install. For instance, Sherex’s SSG-802 spin-spin tool is capable of installing parts with #10, ¼”, M5, and M6-diameter threads, and the SSG-803 is capable of installing 5/16”, 3/8”, M8, and M10-diameter threads. A hydro-pneumatic spin-pull tool is capable of installing all sizes between M3 to M10.
For a job that is consistently is going to use one part and one size, a spin-spin rivet nut tool would be a solid recommendation for the price.

Spin-Pull Rivet Nut Tool

A spin-pull rivet nut tool installs rivet nuts by pulling back its mandrel, rather than spinning it back. The rivet nut spins itself on to the mandrel, and then the mandrel pulls the threads of the rivet nut on to the base material, installing the rivet nut. The tool then spins the opposite way to release installed rivet nut. This tool is also referred to spin-pull-spin as explained in the two sentences before.

Sherex’s Flex-5 line of spin-pull tools is hydro-pneumatic, as the tool uses air and oil to install the part. A spin-pull tool can install everything that a spin-spin tool can, as well as more heavy-duty rivet nuts like full-body hex-style rivet nuts, European body styles, and stainless steel parts.

Another benefit of using a spin-pull tool is that it can install a wide range of thread sizes – from M3 through M10 for metric sizes, and from #4-40 to 3/8”-24 for inch sizes. You would need three different spin-spin tools to install that thread range!

For a job that is consistently is going to use one (compatible) part at one size, a spin-spin rivet nut tool would be a solid recommendation for the price. A spin-spin tool may be heavier and more expensive, but it is a far more versatile tool that can install more styles and more sizes of rivet nuts. All that is needed – for either tool – is the appropriate headset for the thread size you are trying to install.

Need help deciding between a spin-spin tool and a spin-pull tool for your next project? Contact us!

Rivet Nut Corrosion Protection

By Frank Genovese, Applications Engineer, Sherex

There’s always peace of mind knowing that a correctly installed rivet nut is the end of your concerns.

However, there is more to a properly installed rivet nut to ensure its success.

Your rivet nut will be exposed to the outside world of air and moisture, or it may reside in an environment where the piece will be subject to many bumps and scratches throughout its lifetime. While correctly installing the rivet nut is vitally important to its success as a fastener, there’s one more consideration you have to combat when it comes to rivet nut installation —  corrosion.

Corrosion protection for rivet nuts is vitally important when it comes to ensuring the rivet nut will be successful, and there are many ways to combat corrosion.

First, what is corrosion? Corrosion is a surface oxidation process that appears, mainly, in two forms: white rust and red rust.

White Rust a white powder composed of zinc oxide, which eventually coats portions of a surface containing zinc such as the protective layer of zinc-based plating that coats many rivet nuts.

This corrosion does not directly harm the structural integrity of a piece, but makes the piece more vulnerable to a more compromising form of corrosion — red rust, referred to by many as simply “rust.”

Red rust is an iron oxide that physically eats away at the base iron that composes your piece.

So how do you ensure optimal corrosion protection?

Look for rivet nut offerings that are stress-tested with a “salt-spray” test, which subjects rivet nuts to heavy abrasion until rust appears. Rivet nuts coated in a zinc plate with trivalent chromate, which must, at minimum, withstand 96 hours in a salt-spray test before white rust appears with red rust not appearing for another 240 hours. Zinc plate with trivalent chromate comes in clear, yellow, or black options.

For higher corrosion protection, zinc-nickel platings can achieve white-rust times of up to 144 hours minimum, as well as red-rust times of up to 1,200 hours.

If you have rivet nuts that only come in a trivalent plating, a strip and re-plate operation is possible to obtain the plating that best suits you.

The very best option when it comes to corrosion resistance is stainless steel. Stainless steel, though, can be difficult to install so make sure you have the proper tooling to ensure your stainless steel rivet nuts can be installed properly.

If you have any questions regarding which plating or material solution fits your application best please contact us! We are more than happy to give you the information necessary to make an informed decision.

Why Rivet Nuts?

Rivet nuts are becoming more and more popular every year. We would know – we manufacture them.

Their ease of use, high shear and tension strength, and lightning fast installation times are upgrades over traditional bolt and nut, and weld nut applications.

Sherex Rivet Nuts, Knurled Rivet NutsInstalled Rivet NutsA main strength of rivet nuts are that, just like with traditional rivets, they are blind. Meaning, these fasteners can be installed securely from one side of the work piece. No need to struggle to reach around the back of the bolt to fasten the material with a nut. Once the rivet nut is installed, fasten your material through the rivet nut with any compatible externally threaded fastener and you’re all set.

The rivet nut itself can be installed into a variety of a different materials including metal, plastic, fiberglass and carbon fiber. It is used in a wide array of applications in the automotive, heavy truck, and manufacturing industries as they move toward making their products both lightweight and easier to make. In your vehicle, there are likely dozens of rivet nuts for all of the reasons stated above. Lots of them are probably from Sherex!

So how does it work? Installing the rivet nut is easy. Using a hand tool, pneumatic tool, or hydro-neumatic rivet nut tool, place the rivet through a pre-drilled hole. The tool will then crimp the counter-bored section of the rivet nut into the into the back of the installation piece as shown in the .gif below. This leaves the head of the rivet nut laying on top of the material, and the crimped section behind it acting as the nut. That’s really it! In a manufacturing plant, installation can be done through rivet nut automation systems.

Installing a Rivet Nut

 

Check out our rivet nut offerings and see the variety of different styles of rivet nuts which we will hit on in upcoming posts. Some applications need a wider grip range to accommodate larger panel thicknesses, some need stronger spin-out or pull-out loads to withstand a variety of expected loads, and some need different finishes, coatings, and other treatments. We will get into all of those topics later!