You Need a Rivnut Installed and the Tool Is Nowhere in Sight
You’re in the middle of a project—maybe mounting a rack in your van, securing a panel on a motorcycle, or fixing a loose bracket on a piece of furniture. The perfect fastener for the job is a rivnut, also called a threaded insert or a nutsert. It provides a strong, permanent, threaded anchor in thin sheet metal or other hollow materials.
You have the rivnut. You have the bolt. But you reach for the installation tool, and it’s missing, broken, or you never bought one because it’s a specialty tool for a one-time job. The project grinds to a halt. Do you order a tool and wait days, or is there another way?
The good news is, with a little ingenuity, you can install a rivnut without the official tool. This guide will walk you through several proven methods using common tools you likely already have in your garage or workshop. We’ll cover the principles of how a rivnut works, the step-by-step techniques, and crucial tips to ensure your installation is strong and reliable.
Understanding How a Rivnut Works
Before attempting an alternative installation, it’s essential to know what you’re trying to achieve. A rivnut is a two-part fastener. It has a smooth, cylindrical body and an internal threaded section. The magic happens at the base of the body, which has a thin-walled section designed to deform.
During proper installation, the rivnut is inserted into a pre-drilled hole. A special mandrel (the tool’s part) is threaded into the rivnut. When you pull on the mandrel—either with a hand tool, pneumatic tool, or in our case, an alternative—it compresses the rivnut. This compression causes the thin-walled section to bulge outward, forming a blind-side bulge that grips the back of the material tightly. Simultaneously, the top flange is pulled down, clamping the material securely. The result is a flush, permanent nut plate.
Your goal with any alternative method is to replicate that pulling and compressing action. You need to pull on the threads from the front side to make the back side bulge.
Prerequisites and Safety First
Regardless of the method, start with these steps. A clean setup is 90% of a successful installation.
– Drill the correct size hole. This is critical. The hole should be a snug fit for the rivnut’s body. If the hole is too large, the rivnut will spin or not compress properly. If it’s too small, you’ll struggle to insert it and may damage the material. Refer to the rivnut manufacturer’s specifications. As a general rule, for metric rivnuts, the hole size is often the same as the nominal body diameter (e.g., an M5 rivnut might need a 5mm hole).
– Deburr the hole. Use a deburring tool, a larger drill bit by hand, or sandpaper to remove any sharp edges or burrs from drilling. This ensures the rivnut sits flat and the material isn’t stressed.
– Select the right bolt. You will need a standard bolt (not a set screw) that is longer than the rivnut. The bolt’s thread must match the rivnut’s thread perfectly (e.g., M6 bolt for an M6 rivnut). The bolt will be your makeshift mandrel.
– Use two nuts and washers. Have at least two standard hex nuts that fit your bolt, and several washers (standard flat washers and, ideally, one larger fender washer).
– Wear safety glasses. You will be applying significant torque and tension; metal can slip or break.
Method 1: The Two-Nut and Wrench Technique
This is the most common and reliable manual method. It uses the principle of jamming two nuts together on a bolt to create a temporary “tool head” you can grip.
Start by threading your bolt through the front of the workpiece, through the rivnut. The rivnut should be on the back side of your material. Hand-tighten the bolt into the rivnut a few turns, just enough so it’s engaged but not pulling.
Now, on the front side (the bolt head side), thread on the first nut. Follow it with a second nut. Thread the second nut down until it contacts the first nut. Then, using two wrenches, tighten the two nuts against each other. This is called “jamming” or “locking” the nuts. They will now act as a single unit.
Place a large fender washer over the bolt, against the material’s surface. Then, thread the jammed nut assembly down the bolt until it presses firmly against the washer. You are now set up. Hold the bolt head stationary with one wrench to prevent it from spinning. With another wrench, turn the jammed nut assembly clockwise.
As you turn the nut assembly, it will travel down the bolt, pulling the bolt head (and thus the rivnut) toward it. This pulling force compresses the rivnut. You will feel significant resistance increase. Continue turning until the rivnut is fully set. You’ll know it’s set when the bolt becomes very hard to turn, the material is clamped tight, and the rivnut no longer spins. To remove the bolt, simply hold the bolt head and unscrew the jammed nut assembly.
Why a Fender Washer is Key
The large fender washer serves a vital purpose. It distributes the clamping force over a wider area of the material’s surface. Without it, the force from the small nut could dig into or distort thin sheet metal, leading to an uneven or weak installation. Always use one if possible.
Method 2: The Single Nut and Impact Driver Variation
If you have an impact driver or a high-torque drill/driver, you can use a slightly faster method. This works best for smaller rivnuts (M6 and below) in softer materials like aluminum.
Insert the rivnut and thread in your bolt, leaving several threads exposed on the front side. Thread a single hex nut onto these exposed threads. Now, place a socket that fits the nut onto your impact driver. Hold the bolt head absolutely stationary with a wrench or locking pliers. You must prevent the bolt from spinning inside the rivnut.
With the impact driver in forward (tighten) mode, trigger it briefly against the nut. The impacting action will drive the nut down the bolt, pulling the rivnut tight. Use short bursts and check frequently. The risk here is over-compression, as the impact driver can apply enormous force very quickly and potentially strip the threads or shear the bolt. This method requires a more careful touch.
Method 3: Using a Threaded Rod and Coupling Nut
For situations where a bolt is too short, or you need to install many rivnuts, a piece of all-thread (threaded rod) and a coupling nut is an excellent setup. A coupling nut is a long, hexagonal nut designed to join two pieces of threaded rod.
Cut a piece of threaded rod a few inches longer than your rivnut and workpiece thickness. Thread one end into the rivnut. On the front side, slide on your fender washer, then thread the coupling nut onto the rod.
You now have a durable “tool.” Use one wrench on the coupling nut and another on the back side of the threaded rod (you may need a second nut jammed on the back end to get a grip). Turn the coupling nut to compress the rivnut. The advantage is the extra length gives you better leverage, and the coupling nut is stronger than two standard nuts.
Troubleshooting Common Installation Problems
Even with the proper tool, things can go wrong. Here’s how to diagnose and fix issues with your tool-free installation.
The Rivnut Spins Instead of Compressing
This is the most frequent issue. It means the hole is too big. The rivnut needs a tight fit to resist rotation while you pull on the bolt. If it’s already in a oversized hole, your options are limited. You can try applying gentle pressure with pliers on the backside flange to keep it from spinning while you tighten. For a future attempt, the only real fix is to use the correct size hole. If the project allows, you could move to a new, correctly-sized hole location.
The Bolt Breaks or the Threads Strip
This usually means you used a low-grade bolt (e.g., a soft hardware store bolt) or over-torqued it. Rivnut installation requires a high-strength bolt, ideally a grade 8.5 or higher metric bolt (Class 10.9). A weak bolt will stretch, neck down, and snap under tension. Always use a high-quality bolt for these methods.
The Rivnut Compresses Crooked or Unevenly
This can happen if the hole is not clean/deburred, the material is uneven, or the pulling force was not applied straight. Ensure the hole is clean and the rivnut starts square to the surface. Using a large washer helps distribute force evenly and promotes a straight pull.
How Do You Remove a Badly Installed Rivnut?
If you must remove a rivnut, the official method is to drill it out. Use a drill bit slightly smaller than the rivnut’s body diameter to drill through the center, essentially destroying the internal threads. Then, you can often collapse the shell and push it through the hole. Be prepared to clean up the hole afterward, as it may be damaged.
When to Bite the Bullet and Buy the Tool
These methods are perfect for a handful of installations, one-off projects, or emergency fixes. However, they are slower, require more setup, and can be inconsistent compared to a dedicated tool.
If you have more than five rivnuts to install, or if you foresee using them again in the future, investing in a basic hand rivnut tool is highly recommended. A simple lever-action tool is relatively inexpensive and makes the process fast, easy, and reliable. For automotive or fabrication work, it quickly pays for itself in saved time and frustration.
Consider the tool if strength is critical. A dedicated tool applies a more controlled, consistent compression, which can be important for structural or safety-related applications.
Securing Your Project with Confidence
Installing a rivnut without the specialized tool is a classic example of practical problem-solving. By understanding the fastener’s function and using basic mechanical principles, you can replicate the necessary force with items from your toolbox. The two-nut and wrench method is your most reliable bet for a strong, secure installation.
Remember the formula: correct hole size, a high-strength bolt, two jammed nuts, and a large washer. Take your time, apply steady force, and check that the rivnut is fully set and doesn’t spin. This approach will get your project moving again and leave you with a professional-quality result, proving that sometimes the best tool is the one you already know how to use.
