Here's a scenario that comes up constantly in sheet metal and fabrication work: you need to fasten something to thin material with access to only one side. Both pop rivets and rivet nuts install from one side using a pulling tool — but they do completely different jobs. Picking the wrong one means either a joint that can never be disassembled, or a fastening point that can't accept a bolt at all. The distinction is straightforward once you know what each one actually does.
Quick Answer: Use a pop rivet (blind rivet) when you need a permanent, flush connection between two pieces of material and won't need to disassemble the joint. Use a rivet nut (rivnut) when you need to create a reusable threaded hole in thin material — so you can bolt something to it, remove it, and bolt it again. The key difference: pop rivets join two surfaces permanently; rivet nuts add a threaded anchor point.
What Each One Actually Does
Pop Rivets (Blind Rivets)
A pop rivet consists of a hollow body and a mandrel (the stem that pulls through it). When you squeeze the rivet tool, the mandrel pulls the body's tail end into a bulge that clamps against the back of the material. The mandrel then snaps off flush. The result is a permanent, two-piece joint — no threads, no removability.
Pop rivets are fast, require no access to the back of the material, and work across a wide range of material types and thicknesses. The right choice for permanent assemblies: rain gutters, HVAC ductwork, sheet metal panels, boat interiors, and any application where two surfaces need to stay joined. The 200-piece aluminum pop rivet assortment covers 7 SAE sizes (1/8", 3/16", 1/4") — useful when you're working across multiple material thicknesses and don't want to reorder for every job.
Rivet Nuts (Rivnuts / Threaded Inserts)
A rivet nut is a threaded sleeve that's installed into a drilled hole using a rivet nut gun. The tool draws the back end of the sleeve into a flange that grips the back of the material — similar to a pop rivet — but instead of creating a permanent bond between two surfaces, it creates a threaded hole you can use with any standard bolt.
This matters whenever you need to attach something that will eventually be removed: a license plate frame, an equipment rack panel, a trailer component, or anything with access panels. The bolt comes out; the rivet nut stays in permanently, ready for the next installation.
When to Use Each: Five Real Scenarios
| Application | Use This | Reason |
|---|---|---|
| Installing aluminum rain gutter sections | Pop rivet | Permanent joint, no disassembly needed |
| Mounting a removable equipment panel on a steel rack | Rivet nut | Panel needs to come off for maintenance |
| Patching a cracked aluminum toolbox wall | Pop rivet | Structural repair, single-side access |
| Attaching a license plate frame to a thin bumper fascia | Rivet nut | Needs to be removed for inspection or replacement |
| Closing seams on HVAC duct sheet metal | Pop rivet | Permanent seal, no maintenance access required |
The simplest rule: if a bolt needs to go in and come out, you need a rivet nut. If two surfaces just need to be joined permanently, a pop rivet is faster and cheaper.
Load and Strength Considerations
Pop rivets and rivet nuts have comparable tensile and shear load characteristics in similar materials and sizes — neither is generically "stronger" than the other for a holding application. The meaningful difference is in torque resistance.
Pop rivets have no threads. They cannot resist rotational force at all. If you try to use a pop rivet to hold something that gets tightened with a bolt, the rivet will spin in its hole or the connection will fail under torque.
Rivet nuts are designed to accept bolt torque. How much torque a specific rivet nut handles depends on the material (steel vs. aluminum), the size (M5, M6, M8, etc.), the sheet thickness, and installation quality. Always check the manufacturer's specifications for the rivet nut and size you're using — don't apply generic torque figures across different products or materials.
For vibration resistance, a rivet nut with thread-locking compound on the bolt (Loctite or equivalent) is more reliable long-term than a pop rivet in applications where vibration could work the joint loose — since the bolt can be re-tightened if needed.
How to Install a Rivet Nut: Step by Step
Rivet nuts require a dedicated rivet nut gun — a standard pop rivet gun cannot generate the controlled pulling force needed to properly set a threaded insert. The mechanism is fundamentally different: a pop rivet gun pulls and snaps a mandrel; a rivet nut gun pulls a threaded mandrel under controlled tension, then backs out.
- Select the correct rivet nut size for your bolt. Check the rivet nut manufacturer's specification sheet for the correct hole diameter for your material thickness — using the wrong hole size is the most common cause of installation failure.
- Drill the hole cleanly and deburr the edges. A rough or oversized hole prevents the rivet nut from seating correctly.
- Thread the rivet nut onto the mandrel of the rivet nut gun by spinning the nut clockwise until it's snug against the nose piece.
- Insert the rivet nut into the hole until the flange is flush against the material surface.
- Operate the gun — squeeze the handles evenly until the rivet nut is fully set. The tool pulls the body of the nut, collapsing the back end into a flange that clamps the material between the front flange and the back collar.
- Test by threading in the correct bolt by hand. It should spin freely without resistance and seat firmly when tightened. If the nut spins in the hole, the hole was too large or the nut wasn't fully set.
The 16" rivnut tool kit with 200-piece assortment includes 15 metric and SAE mandrels and a carrying case — a practical setup if you're working across M4 through M12 or mixing metric and standard inserts in the same project. For lighter use, the 16" rivet nut gun with 15 mandrels covers the most common sizes without the full assortment kit.
Material Compatibility
- Aluminum rivet nuts in aluminum sheet: appropriate match, avoids galvanic corrosion between dissimilar metals
- Steel rivet nuts in steel sheet: standard for most structural applications
- Stainless steel rivet nuts: for outdoor or marine applications where corrosion resistance is the priority; requires a heavier-duty tool due to higher installation force
- Aluminum rivet nuts in composite or fiberglass: the lower installation force of aluminum inserts reduces the risk of delaminating brittle materials
Avoid installing steel rivet nuts in aluminum sheet in outdoor or wet environments — the contact between dissimilar metals in the presence of moisture causes galvanic corrosion that weakens the joint over time.
Common Mistakes
- Using a standard pop rivet gun to try to set a rivet nut. The tools are not interchangeable — attempting this damages both the tool and the insert.
- Drilling the hole without checking the rivet nut spec sheet for diameter. Hole diameter tolerance is tight for rivet nuts — too large and the nut spins; too small and it won't insert fully.
- Installing steel rivet nuts in aluminum in outdoor environments. Galvanic corrosion will eventually loosen the installation in the presence of moisture.
- Assuming bigger is always better on rivet nut size. A larger rivet nut needs a larger hole, which removes more material from what may already be a thin or small part. Match the size to the actual bolt load requirement.
- Not deburring the drilled hole. Burrs on the hole edge prevent the rivet nut flange from seating flush, resulting in an installation that's off-angle or that can work loose.
FAQ
I installed a rivet nut and now it spins every time I try to tighten a bolt into it — what went wrong?
Almost always one of two things: the hole was drilled slightly too large, so the nut can't grip the material, or the nut wasn't fully set during installation (the gun wasn't pulled far enough to fully collapse the back flange). Drill it out, check your hole diameter against the specification for your rivet nut size, and reinstall. If the original hole is now too large, shift to a fresh location or step up to the next rivet nut size.
Can I install a rivet nut with a pop rivet gun?
No. Pop rivet guns pull and snap a mandrel. Rivet nut guns pull a threaded mandrel under controlled tension and then back out. The mechanism is fundamentally different, and attempting to use a pop rivet gun on a rivet nut will damage both the tool and the insert.
Is a rivet nut permanent once installed?
The rivet nut itself is permanent — it's deformed during installation and cannot be removed without drilling it out. The bolt that threads into it is fully removable and reusable, which is the point of the system.
What rivet nut size do I need for an M6 bolt?
An M6 rivet nut accepts an M6 bolt. The drill bit size you need for the hole depends on the specific rivet nut brand and material thickness — check the spec sheet for your rivet nut, as this varies between manufacturers.
Can I convert an existing pop rivet hole to a rivet nut hole?
Sometimes. Drill out the existing rivet, check whether the hole size is correct for your rivet nut (you may need to slightly enlarge it), and confirm the surrounding material is still structurally sound. If the material around the original hole is deformed or weakened, choose a new location.
Choose Based on Whether You Need Threads
The decision between a pop rivet and a rivet nut comes down to one question: does a bolt need to go into this joint, and does it need to come back out? If yes — rivet nut. If the joint is permanent — pop rivet.
If you're setting up for rivet nut work, see the rivet nut gun kit details for included mandrel sizes and compatible insert ranges.
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