Use Rivnuts For Stronger, Removable Fittings for Sheet Metal Fabrication (Updated for 2025)

Last updated on January 13th, 2025 at 09:07 am

When you’re assembling a series of industrial sheet metal components, it’s important to use fasteners that have strong, load-bearing threads and won’t easily strip out under pressure.

Screws, bolts, and rivets are good examples of common mechanical fasteners that work to secure components with substantial holding power.

But what if you need a fastening system that allows you to attach and remove linked pieces in your assembly?

Rivnuts are a strong, durable, and removable solution for assembling and disassembling custom sheet metal components as needed and with ease.

The Benefits of Using Rivnuts for Stronger, Removable Fittings

Rivnuts, also commonly referred to as rivet-nuts, are hardware components used to fasten two pieces of sheet metal together.

A rivnut is tubular in shape. Much like a regular rivet, it’s placed into a pre-drilled hole and bucked into place either by hand or with pneumatic or hydropneumatic tools. Once installed, it creates a permanent internal thread in a piece of sheet metal. Add a proper sized bolt and you can fasten (and unfasten) anything to it!

 

There are many benefits to using rivnuts for your assemblies:

• Adding strong load-bearing threads to thin or weak sheet metal parts.

Rivnuts allow you to thread into panels that are normally too thin or weak for threads. Buckling a rivnut during installation forms a nub on the back side of the panel, providing a strong anchor that’s much more durable than tapping and can’t be pulled out easily.

• Access to blind locations.

Rivnuts are blind threaded inserts, which means they can be installed securely from one side of a workpiece. Blind inserts are perfect for applications like tubular frames [link to New Capability: Stainless Steel Tubular Frames for the Medical Industry] and other parts that are difficult to reach into.

• Assembling and disassembling components with ease.

The ability to take apart and reattach assemblies is important for a number of applications such as chassis, indoor and outdoor furniture, car dashboard attachments, bicycles, and solar panels. Rivnuts offer a simple and practical solution that’s not only extremely durable, but also quick and cost-efficient.

• Scratch and damage-free installations.

No more worrying about scratched surfaces! Rivnut installation doesn’t require heat, electricity, or tapping, so it’s generally a damage-free process. Plus, the lack of heat application makes it possible to install rivnuts in a variety of materials including steel, plastic, and even fiberglass.

Rivnuts come in many shapes, sizes, and styles (e.g. flathead rivnuts, ribbed rivnuts, countersunk rivnuts). The simplest way to include rivnuts in your sheet metal assembly is to call them out in your drawing or model. Here’s a handy chart for guidance.

Material Compatibility and Selection

Choosing the appropriate material for rivnuts is crucial for ensuring compatibility with the sheet metal material and meeting the specific requirements of your application. Key factors to consider include:

• Material Types: Rivnuts are commonly available in steel, stainless steel, and aluminum. Selecting the appropriate material depends on factors such as corrosion resistance, strength requirements, and compatibility with the sheet material. For instance, stainless steel rivnuts offer excellent corrosion resistance, making them suitable for applications exposed to harsh environments.
• Corrosion Resistance: The selection of the material type and coating of the rivet nut should be made on the basis of the corrosion resistance required.
• Surface Treatment: Steel rivnuts are often zinc plated to enhance corrosion resistance. The standard supplied surface treatment is 8µ zinc plated, chrome-free iridescent passivated.

Design Considerations and Limitations

Proper design and installation of rivnuts are vital to ensure their effectiveness and longevity. Consider the following:

• Hole Preparation: Ensure that the hole dimensions match the rivnut specifications. For instance, the hole diameter for cylindrical holes and the across-the-flats dimension for hexagonal holes should be precise to prevent issues during installation.
• Installation Access: Rivnuts are blind threaded inserts, which means they can be installed securely from one side of a workpiece. This feature is particularly beneficial for applications like tubular frames and other parts that are difficult to reach into.
• Load Requirements: Assess the load-bearing requirements of your application to select rivnuts with adequate strength. For example, a properly installed 1/4-20 rivnut in 0.030 rolled steel has a 480-pound pullout strength, so four will provide a significant margin for a 145-pound dead weight.
• Installation Tools: ASM uses appropriate installation tools to ensure proper setting of rivnuts. Improper installation can lead to issues such as reduced load capacity or loosening over time. High-quality socket-head cap screws (mandrels) of the correct length are recommended for optimal installation.
• Material Thickness: Measure the thickness of the shet material to ensure it falls within the rivnut’s grip range. Selecting the correct rivnut length based on material thickness is essential for secure fastening. For instance, if you have a choice between two rivnuts in the allowable tolerance range, select the shorter rivnut if the workpiece is hard.

That said, when you work with our sheet metal fab shop, we’re happy to pick and source your rivnuts for you! We’re experts at installing rivnuts, so we can take care of the entire process-from sourcing through assembly. Request a quote today!

Sheet Metal Hardware Hole Sizes Chart

CHART DOWNLOAD

Hardware hole sizes are the number one thing sheet metal fabricators have to fix before sending a part to the floor. So we have created a referenceable chart for product developers that are designing sheet metal parts. Use this chart to find the correct hole size for the hardware you select.

Get it now

Sheet Metal Rivnut FAQ

What are rivnuts and how do they work?

Rivnuts, also known as rivet-nuts, are tubular hardware components used to fasten two pieces of sheet metal together. They are placed into pre-drilled holes and bucked into place, creating a permanent internal thread in the sheet metal. This allows you to attach and detach components easily using proper-sized bolts.

What are the benefits of using rivnuts in sheet metal assemblies?

here are several benefits of using rivnuts:

• Adding strong load-bearing threads to thin or weak sheet metal parts.
• Access to blind locations for secure installation.
• Ease of assembling and disassembling components.
• Scratch and damage-free installations.
• Versatility in materials and styles.

Can rivnuts be used in applications with thin or weak sheet metal?

Yes, rivnuts are particularly useful for adding load-bearing threads to thin or weak sheet metal parts. By buckling a rivnut during installation, it creates a durable anchor that is stronger than tapping and less likely to be pulled out easily.

Are rivnuts suitable for hard-to-reach areas in assemblies?

Absolutely! Rivnuts are blind threaded inserts, allowing for secure installation from one side of the workpiece. This feature makes them ideal for applications with blind locations or parts that are difficult to reach into, such as tubular frames or similar components.

Are rivnuts installation-friendly and compatible with various materials?

Yes, rivnut installation is a simple and practical solution. It doesn’t require heat, electricity, or tapping, making it a damage-free process. Additionally, rivnuts can be installed in a variety of materials, including steel, plastic, and fiberglass. They come in different shapes, sizes, and styles to suit your specific needs.