Add strong, reusable threads to sheet metal, plastic, and composites when tapping isn’t practical and backside access isn’t possible.
Rivet nuts are one of the most reliable ways to create permanent internal threads in thin materials. They install from one side, clamp tightly during setting, and support repeated bolt installation without damaging the parent material.
Overview
A rivet nut, also called a nutsert or threaded insert, is a blind fastener that adds permanent internal threads to material that is too thin for traditional tapping.
The fastener is placed into a pre-drilled hole and installed using a specialized tool. As it sets, the back side collapses and clamps against the material, creating a secure threaded insert that can accept bolts or screws repeatedly.
Because rivet nuts install from one side only, they’re ideal for enclosed assemblies, tubing, panels, and applications where the back side of the material can’t be reached.
Install from one side of the workpiece when backside access is limited or impossible.
Create reliable threads in thin material that cannot be tapped effectively.
Allow bolts and screws to be installed and removed without wearing out the parent material.
Selection Basics
Most rivet nut selection issues come down to matching the thread, the material thickness, and the torque demands of the application.
Choose a rivet nut with internal threads that match the final bolt or screw. Common options include metric sizes like M4, M5, and M6, or inch threads such as UNC and UNF.
Starting with the mating fastener spec helps prevent cross-threading, stripping, and compatibility problems.
Grip range is the thickness span the rivet nut is designed to clamp once installed.
If the material is too thin, the insert may not expand properly and can spin. If the material is too thick, it may not collapse correctly during installation.
Body length affects how the insert collapses during installation and is usually tied closely to grip range.
In practice, choosing the right grip range usually gets you to the correct body length as well.
Body Styles
Body style affects installation requirements, anti-rotation performance, and cost.
Round body rivet nuts are the most common general-purpose style. They install into a standard round hole, making them simple to specify and easy to install.
They work well when torque loads are moderate, but may be more likely to spin in very smooth or thin materials than more aggressive anti-rotation designs.
Knurled rivet nuts have serrations on the outer body that bite into surrounding material during installation.
They’re a strong option for softer materials like aluminum or plastic where extra torque resistance helps prevent spinning during assembly or service.
Half hex rivet nuts combine a hex upper section with a round lower section.
They lock into a hex hole for better anti-rotation performance while staying easier to install and generally more cost-effective than full hex options.
Full hex rivet nuts are designed for maximum anti-rotation performance.
Because the entire body engages a hex hole, they resist spinning under high torque and vibration, making them a good fit for demanding assemblies and heavier-duty equipment.
Head Styles
Flat head rivet nuts use a wider flange to spread load across the material surface and reduce pull-through risk.
Reduced head rivet nuts use a smaller flange for tighter spaces and a lower-profile look, with slightly less load distribution than flat head styles.
Countersunk rivet nuts sit flush when installed into a countersunk hole, making them a good fit where the surface needs to stay flat.
End Configuration
Open-end rivet nuts are threaded through the full body and are the most common option for general fastening applications.
They allow bolts to pass through the full insert length and give you flexibility across a wide range of assemblies.
Closed-end rivet nuts use a sealed bottom to help block liquids, dirt, and debris from passing through the fastener.
They’re useful in automotive panels, outdoor equipment, and electrical enclosures where thread protection and environmental sealing matter.
Quick Comparison
| Need | Best Starting Point | Why |
|---|---|---|
| General-purpose installation | Round body / flat head | Easy hole prep, broad availability, reliable for many standard assemblies |
| Better torque resistance in softer materials | Knurled body | External serrations improve grip in aluminum and plastics |
| Better anti-rotation without full hex cost | Half hex body | Strong balance of performance, installation ease, and value |
| Highest torque resistance | Full hex body | Full engagement in hex hole reduces spinning under load |
| Flush finished surface | Countersunk head | Sits level with the material surface after countersinking |
| Better sealing against contaminants | Closed-end design | Helps block moisture, dirt, and debris from passing through |
Selection Guide
Rivet nuts are a practical way to add durable internal threads to thin materials when traditional nuts or tapped holes aren’t a good fit. With the right thread, grip range, body style, and head style, you can build a more secure and serviceable assembly.