Rivet Nut Size Chart
A rivet nut size chart is a reference guide that lists various rivet nut sizes along with their corresponding specifications—such as body diameter, thread type, recommended hole size, and grip range. Its main purpose is to help users select the correct rivet nut and matching hole size to ensure a secure, strong, and reliable installation. By using the chart, you can avoid issues like loose fitting, spinning, or poor fastening performance during assembly.
Metric Rivet Nut Size Chart
| Nut Size | Thread Type | Body Diameter (mm) | Recommended Hole Size (mm) | Grip Range (mm) |
| M3 | Metric | 4.9 – 5.0 | 5.1 – 5.3 | 0.5 – 1.5 |
| M4 | Metric | 6.0 – 6.1 | 6.3 – 6.5 | 0.5 – 2.0 |
| M5 | Metric | 6.8 – 7.0 | 7.1 – 7.3 | 0.5 – 3.0 |
| M6 | Metric | 8.8 – 9.0 | 9.1 – 9.3 | 0.5 – 3.5 |
| M8 | Metric | 10.7 – 11.0 | 11.1 – 11.3 | 0.5 – 4.5 |
| M10 | Metric | 12.8 – 13.0 | 13.1 – 13.3 | 0.5 – 5.5 |
| M12 | Metric | 14.8 – 15.0 | 15.1 – 15.3 | 1.0 – 6.0 |
Inch Rivet Nut Size Chart
| Nut Size | Thread Type | Body Diameter (mm) | Recommended Hole Size (in/mm) | Grip Range (mm) |
| #6-32 | UNC | ~5.0 | 0.208 in / 5.3 mm | 0.5 – 1.5 |
| #8-32 | UNC | ~6.3 | 0.250 in / 6.35 mm | 0.5 – 2.0 |
| #10-24 | UNC | ~7.0 | 0.266 in / 6.76 mm | 0.5 – 3.0 |
| #10-32 | UNF | ~7.0 | 0.266 in / 6.76 mm | 0.5 – 3.0 |
| 1/4″-20 | UNC | ~9.0 | 0.344 in / 8.74 mm | 0.5 – 3.5 |
| 5/16″-18 | UNC | ~11.0 | 0.437 in / 11.10 mm | 0.5 – 4.5 |
| 3/8″-16 | UNC | ~13.0 | 0.500 in / 12.70 mm | 0.5 – 5.5 |
| 1/2″-13 | UNC | ~15.0 | 0.656 in / 16.66 mm | 1.0 – 6.0 |
⚠️ Notes:
- The recommended hole size should be about 0.1–0.3 mm larger than the rivet nut body to allow for easy insertion while ensuring a snug fit that prevents spin or loosening.
- Hex body rivet nuts require hexagonal holes or anti-rotation features. Make sure to confirm the hole shape and tolerance during installation planning.
- Different materials (steel, aluminum, plastic, etc.) may affect hole size tolerances. Always test and verify fit according to the actual application.
Selecting the appropriate rivet nut size requires considering several factors, including sheet thickness, thread requirements, application environment, and available installation space. Below are the key points in detail:
1. Choose Based on Grip Range (Sheet Thickness)
The “Grip Range” of a rivet nut indicates the thickness of material it is designed to fasten. Make sure the material thickness falls within the specified range:
- If the sheet is too thin, the rivet nut may not be securely fastened.
- If the sheet is too thick, the rivet nut may not deform properly during installation, leading to poor anchoring.
2. Match the Thread Size to Your Fastener
Select the rivet nut thread size based on the bolt or screw you plan to use:
- For example, if you’re using an M6 bolt, choose a rivet nut with an M6 internal thread.
- For inch sizes like 1/4”-20 or #10-32, make sure the thread matches accordingly.
Proper threading prevents stripping or loose fastening during use.
3. Select the Material Based on the Environment
Different materials suit different usage environments:
- Stainless Steel: Excellent corrosion resistance; ideal for outdoor, marine, or high-humidity applications.
- Steel: High strength and commonly used for mechanical or structural assemblies.
- Aluminum: Lightweight and corrosion-resistant; suitable for plastics or lightweight materials.
4. Choose the Right Head Style Based on Space Constraints
Rivet nuts come with different head styles, affecting both the installation method and the final appearance:
- Flat Head: Common for standard surface mounting; suitable for most applications.
- Countersunk Head: Used when a flush surface is needed for aesthetic or functional reasons.
- Reduced Head: Ideal for confined spaces or close-to-edge installations.
How Does Material Thickness Affect Rivet Nut Selection?
When selecting a rivet nut, material thickness (i.e., the thickness of the sheet to be fastened) is one of the most critical factors. The grip range indicates the thickness range in which a rivet nut can be effectively installed.
a. What Happens If Material Thickness Is Less Than the Grip Range
- The rivet nut may not fully expand and could rotate or fall out.
- The joint may be loose, reducing clamping force and strength.
- A shorter or thin-wall rivet nut is recommended in this case.
b. What Happens If Material Thickness Is Greater Than the Grip Range
- The rivet nut will not fully deform and cannot be properly installed.
- Installation may damage the nut or cause thread stripping.
- An extended or extra-long grip range rivet nut is required.
c. Best Practices for Choosing the Right Grip Range
- Measure the actual material thickness using a caliper or thickness gauge.
- Select a grip range that includes your thickness in the middle range, not at the extreme ends.
- Example: For a 2.5mm thick sheet, choose a grip range of 1.0–3.5mm rather than 2.0–5.0mm.
- If installing on stacked or layered materials, add all layer thicknesses together.
- For structural or high-load joints, allow a safety margin of 0.2–0.5mm in grip range.
Do Rivet Nut Types Require Different Hole Shapes?
The choice of hole shape is critical when installing rivet nuts, as it directly affects the nut’s resistance to rotation, installation security, and overall compatibility. Different types of rivet nuts require different hole shapes—this cannot be ignored.
- Recommended Hole Shape: Standard round hole.
- Application: Suitable for low-torque environments, such as manual assembly or single-use fastening.
- Advantages: Easy to install, low drilling requirements.
- Note: Prone to spinning under torque or vibration. Not ideal where anti-rotation is essential.
- Recommended Hole Shape: Standard round hole (with tighter tolerance).
- Features: The knurled or ribbed exterior increases friction with the hole wall.
- Advantages: Improved anti-rotation capability, suitable for soft materials (e.g., aluminum, plastic) or light vibration conditions.
- Recommendation: Use with precisely controlled hole diameters for optimal performance.
- Recommended Hole Shape: Hexagonal hole or round hole with anti-rotation slots.
- Features: Naturally resists spinning due to its shape; ideal for high-torque or frequent-use applications.
- Advantages: Strongest anti-rotation performance, excellent for heavy-duty applications.
- Note: Requires more precise hole preparation, usually through laser cutting, punching, or custom machining.
What Tools Are Recommended for Installing Rivet Nuts Correctly?
Choosing the right tools is crucial for achieving a strong, reliable rivet nut installation. It directly affects the firmness of the joint, anti-rotation performance, and suitability for batch production. Below are common tool types and installation recommendations:
- Applicable Scenarios: Small batch, maintenance, or manual assembly.
- Advantages:
- Low cost and flexible operation;
- Suitable for locations without electricity or air supply;
- Can be used in tight spaces.
- Disadvantages:
- Lower installation efficiency;
- Heavily dependent on operator skill;
- Torque control is unstable, which may cause poor clamping or damage to the nut.
- Applicable Scenarios: Medium volume production, assembly lines.
- Advantages:
- Easy and less labor-intensive operation;
- More consistent installation quality;
- Some advanced models have torque setting features to ensure uniform crimping force every time.
- Disadvantages:
- Moderate to high cost;
- Requires power supply, less flexible in some environments.
- Applicable Scenarios: Heavy-duty industrial assembly, high-volume production lines.
- Advantages:
- Fast installation speed and high efficiency;
- Stable torque output, ideal for repetitive tasks;
- Better suited for larger sizes like M8, M10, M12.
- Disadvantages:
- Requires compressed air supply;
- Higher initial equipment investment;
- Not suitable for workstations requiring high mobility.
How to Ensure the Rivet Nut Does Not Loosen or Rotate After Installation?
- Select Proper Hole Size and Nut Type: For high anti-rotation requirements, prioritize knurled or hex body rivet nuts.
- Control Crimping Torque or Pull Force: Use electric or pneumatic tools with torque adjustment to avoid over- or under-tightening.
- Use Reliable Clamping Fixtures: Ensure the rivet nut is tightly and evenly pressed against the workpiece during installation to prevent misalignment or thread stripping.
Is Torque Control Necessary?
It is recommended to use tools with torque setting in the following cases:
- High-strength joint requirements (e.g., mechanical structures, automotive parts);
- Softer materials such as aluminum or plastic sheets;
- Frequent repetitive installation operations;
- Industrial assemblies with strict quality standards.
FAQs
1. Can Rivet Nuts Be Reused?
In general, rivet nuts are not recommended for reuse, especially after being installed and then removed. Reasons include:
- After installation, the deformed section of the nut undergoes plastic deformation, and reinstallation may not provide reliable clamping force.
- Reusing the nut may cause it to spin, loosen, or damage the internal threads.
- If repeated assembly is required, consider threaded inserts or removable rivet nut designs instead.
2. What If the Hole Is Too Large?
If the drilled hole is oversized, the rivet nut may rotate, loosen, or fail to clamp properly. Solutions include:
- Use a larger size rivet nut and reinstall.
- If the hole cannot be modified, consider rivet nuts with larger outer diameters or knurled/splined bodies to improve anti-rotation performance.
- In extreme cases, reinforce the base material or use metal repair rings or inserts to restore the hole size.
3. Can I Use Inch Drill Bits for Metric Rivet Nuts?
Yes, but you must ensure that the inch drill bit matches the recommended metric hole size. Some common inch drill bits like F drill, #11, or #25 are often used as equivalents. Recommendations:
- Refer to a drill size conversion chart to find the closest match.
- Use a caliper or plug gauge to verify the actual hole diameter, especially for precision applications.
- Avoid using oversized inch drill bits, as this can lead to loose fitting and poor performance.
4. What Are the Differences Between Rivet Nut Head Styles and When to Use Them?
Rivet nuts come in various head styles such as Flat Head, Countersunk Head, and Reduced (Small) Head, each suited for specific installation needs:
- Flat Head: Most common; suitable for general sheet metal applications.
- Countersunk Head: Ideal for applications that require a flush surface, such as electronic enclosures or aesthetic panels.
- Reduced Head: Used in tight spaces or with thin materials where standard heads are too large.
