How to Choose the Correct Rivet or Rivet Nut
, by findmallindustry, 5 min reading time
Blind rivets create permanent joints, while rivet nuts add reusable internal threads to thin material. Correct selection starts with access, material thickness, hole size, load, and environment.
Blind rivets and rivet nuts are both installed from one side of a workpiece, but they perform different jobs. A blind rivet permanently joins layers together. A rivet nut installs a threaded insert so a bolt or screw can be removed and reinstalled later.
Choosing between them - and selecting the correct size - requires more than matching the hole diameter.
Choose the Fastener Type First
Use a Blind Rivet When:
• You need a permanent joint.
• Only one side of the assembly is accessible.
• The connected sheets or components will not require regular disassembly.
• The joint design and specified rivet meet the required shear and tensile loads.
Use a Rivet Nut When:
• You need a reusable internal thread.
• The base material is too thin to tap reliably.
• Welding a nut is undesirable or backside access is limited.
• A panel, bracket, cover, handle, or accessory may need future removal.
A rivet nut is not simply a larger blind rivet. It must resist spinning and pull-out when the mating bolt is tightened or loaded.
Measure the Total Grip Thickness
Grip range is the total thickness of the material being clamped, not the length of the fastener and not the diameter of the hole.
For a blind rivet, add the thickness of every layer in the joint and choose a rivet whose published grip range includes that total. A rivet outside its grip range may not form the correct blind-side head or clamp the joint securely.
For a rivet nut, measure the thickness of the single panel or combined material where the insert will collapse. Choose the specified grip range for that thickness.
Use the Recommended Hole Size
The hole must match the fastener manufacturer's specification. An undersized hole can damage the fastener or prevent insertion. An oversized, irregular, or heavily burred hole can reduce clamp quality and allow a rivet nut to rotate.
Drill or punch a round hole, remove harmful burrs, and keep the hole within the recommended tolerance. Do not select a replacement fastener by visual comparison alone.
Select Diameter and Strength
Fastener diameter affects joint strength, but increasing diameter is not a substitute for correct joint design. Consider:
• Shear load across the joint
• Tensile or pull-apart load
• Number and spacing of fasteners
• Edge distance
• Vibration and fatigue
• Strength of the joined material
For structural, lifting, vehicle, pressure, or safety-critical work, use an engineered specification rather than a general buying guide.
Match the Fastener Material to the Assembly
Common choices include aluminum, steel, and stainless steel. The best material depends on required strength, weight, corrosion exposure, temperature, and compatibility with the joined materials.
Contact between dissimilar metals can promote galvanic corrosion in the presence of an electrolyte such as water or salt spray. Coatings, sealants, compatible material pairs, or isolation methods may be required in outdoor and marine environments.
Select the Head and Body Style
Blind rivet head styles may include dome, large flange, or countersunk designs. A large flange can spread load over softer or thin material, while a countersunk head may provide a flush surface when the joint is prepared for it.
Rivet nut bodies may be round, knurled, ribbed, hexagonal, open end, closed end, reduced head, or large flange. Anti-rotation features can be valuable, but the panel and hole must be prepared for that design. A hex-body rivet nut, for example, requires the correct matching hole shape.
Confirm Thread Size for Rivet Nuts
Match the internal thread to the mating bolt by diameter and pitch. Do not mix metric and inch fasteners, and do not assume two bolts of similar outside diameter share the same thread.
Also confirm that the available thread engagement is sufficient for the application and that bolt tightening torque will not exceed the insert or base material limits.
Use a Compatible Installation Tool
Blind rivets require a rivet tool that accepts the rivet diameter and mandrel. Rivet nuts require the correct mandrel and nosepiece for the thread size. The tool's setting method and stroke must suit the insert.
Under-setting can leave the fastener loose. Over-setting can strip threads, distort the panel, or damage the insert. Set up and test the tool on scrap material of the same type and thickness before working on the final part.
Common Selection Mistakes
• Confusing rivet length with grip range
• Ignoring the manufacturer's hole-size tolerance
• Mixing metric and inch threads
• Selecting only by diameter without checking strength
• Using incompatible metals in a wet environment
• Installing with the wrong nosepiece or mandrel
• Applying uncontrolled force instead of following the tool setup instructions
Frequently Asked Questions
Can a rivet nut replace a welded nut?
It can in many thin-sheet and one-sided-access applications, but load, temperature, vibration, thread strength, and installation quality must be evaluated for the specific joint.
How do I know what rivet length I need?
Measure the total material thickness and select a rivet whose published grip range includes it. Do not select by overall rivet length alone.
Why does a rivet nut spin in the hole?
Common causes include an oversized or damaged hole, the wrong body style, insufficient setting force, material outside the grip range, or excessive bolt-tightening torque.