Plus Nuts Vs Rivet Nuts – Choosing The Right Fastener For Your Project

ByJim Boslice Metalworking & Fabrication

Rivet nuts are ideal for thin sheet metal where you need a quick, reliable thread. Plus nuts are better for uneven holes or softer materials because their slotted legs expand to grip a wider surface area.

You have finally finished mocking up that custom bracket in your garage, but now you face a classic problem: how do you securely attach it to a hollow frame or thin sheet metal without access to the backside? This is the exact moment every DIYer finds themselves weighing the pros and cons of plus nuts vs rivet nuts.

I have spent years building custom van interiors and fabricating metal components, and I have learned the hard way that picking the wrong fastener leads to spinning inserts and loose connections. You deserve a solution that holds tight for the long haul, so let’s dive into which hardware belongs in your workshop.

By the end of this guide, you will know exactly when to reach for a standard rivet nut and when the unique design of a plus nut is worth the extra investment. Let’s get your project secured the right way.

Understanding the Basics of Plus Nuts vs Rivet Nuts

At their core, both of these fasteners are designed to create a threaded hole in materials where you cannot reach the back side. Think of them as a blind fastener—once installed, they provide a permanent, threaded anchor for your bolts.

Standard rivet nuts, often called nutserts, consist of a simple cylindrical body with internal threads. When you use an installation tool to pull the mandrel, the body collapses and forms a bulge on the backside of the material.

Plus nuts operate on a similar principle but feature a distinct design advantage. They have a pre-slotted body that splits into several “legs” when compressed, creating a much larger footprint on the rear side of the panel.

When to Choose a Standard Rivet Nut

Standard rivet nuts are the industry workhorse for thin-gauge steel or aluminum. If you are working with material that has a consistent thickness and a clean, tight-fitting hole, these are your best friend.

They are incredibly cost-effective and available in a massive range of sizes and materials, from zinc-plated steel to stainless steel. Because the footprint is relatively small, they work perfectly in tight spaces where you do not have much room behind the panel.

However, they do have a limitation. If your hole is slightly oversized or the material is very thin, the rivet nut may not have enough surface area to grip, leading to the dreaded “spinning insert” that ruins your day.

Why Use Plus Nuts for Challenging Applications

Plus nuts are essentially the heavy-duty, problem-solving cousin of the rivet nut. Because they feature those slotted legs, they are much more forgiving when it comes to hole tolerance and material thickness.

These fasteners are the gold standard for DIYers working on van conversions or installing roof racks. They handle uneven surfaces with ease because the legs splay out to grab the metal, distributing the load over a larger surface area.

Another major benefit is their ability to work in soft materials. If you are working with fiberglass or plastic, a standard rivet nut might crack the material, but a plus nut’s wide, petal-like expansion provides a secure, non-damaging grip.

Essential Tools for Successful Installation

Whether you choose a plus nut or a rivet nut, your installation is only as good as your tool. While you can technically use a bolt and a nut to manually compress these, I highly recommend a dedicated rivet nut tool.

Look for a tool that offers a long handle for leverage, as compressing these fasteners takes significant force. If you are doing a large project, a pneumatic or cordless electric tool will save your hands from extreme fatigue.

Always double-check your drill bit size before you start. A loose hole is the fastest way to cause a failure. Use a sharp, high-quality cobalt drill bit to ensure the hole remains perfectly circular and free of burrs.

Step-by-Step Installation Technique

To ensure your fasteners stay put, follow these professional steps for a solid installation:

  1. Prepare the hole: Drill your hole to the exact specification provided by the manufacturer. Use a deburring tool to clean the edges, as metal shavings prevent a flush fit.
  2. Thread the fastener: Screw the rivet nut or plus nut onto the mandrel of your installation tool until it is seated firmly.
  3. Insert and compress: Place the fastener into the hole. Apply steady pressure with the tool and actuate the handle to compress the body.
  4. Check the tension: Once you feel the resistance increase, stop. Over-tightening can strip the internal threads, making the fastener useless.
  5. Test the fit: Thread a test bolt into the insert to ensure it is straight and secure before mounting your final component.

Common Pitfalls and How to Avoid Them

The most common mistake is failing to account for the grip range of the fastener. If your material is 0.040 inches thick and you use a fastener designed for 0.125 inches, it will not collapse correctly and will eventually rattle loose.

Another frequent issue is using a zinc-plated steel fastener on an aluminum frame. This creates a galvanic corrosion reaction, where the two metals eat each other over time. Always try to match your fastener material to the base metal.

Finally, do not be afraid to use a drop of thread locker on your final bolt installation. It acts as an insurance policy against vibrations, especially if you are working on a vehicle that sees a lot of road time.

Frequently Asked Questions About Plus Nuts vs Rivet Nuts

Can I remove a rivet nut once it is installed?

Removing them is difficult but possible. You can carefully drill out the head of the rivet nut using a bit slightly larger than the body diameter, then push the remaining sleeve into the cavity. Be careful not to enlarge the original hole in the process.

Do I need a special tool for plus nuts?

While some specialized plus nuts can be installed with a standard rivet nut tool, many require a specific adapter or a tool designed to handle the larger expansion of the legs. Always check the manufacturer’s data sheet.

Are plus nuts stronger than standard rivet nuts?

In terms of pull-out strength, yes. Because they expand into a wider “star” shape, they are much harder to pull through the hole, making them superior for high-vibration or load-bearing applications.

Which is better for thin sheet metal?

For very thin sheet metal, standard rivet nuts are usually sufficient, provided the hole is perfectly sized. If the metal is prone to deformation, the plus nut is the safer bet because it puts less stress on the immediate hole edge.

Your workshop projects are only as strong as your connections. By understanding the mechanical differences between these fasteners, you can stop guessing and start building with confidence. Whether you are reinforcing a chassis or mounting a shelf, choosing the right hardware ensures your hard work stands the test of time. Keep your drill sharp, measure twice, and don’t hesitate to reach for the plus nut when the situation calls for a little extra grip. Happy building!

Jim Boslice
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