Rivet Nut Grip Range Chart
Choosing the right rivet nut starts with understanding its grip range—the thickness of material it’s designed to securely fasten. Our rivet nut grip range chart provides essential data to help you select the correct fastener for your application. Whether you’re working with thin sheet metal or layered composites, using the appropriate grip range ensures optimal clamping force, structural integrity, and long-term performance. Explore the chart below to find the best fit for your project needs.
Rivet Nut Grip Range Chart – Metric
| Thread Size | Nut Type | Grip Range (mm) | Body Length (mm) | Head Type | Hole Size (mm) |
| M3 | Round Body | 0.5 – 1.5 | 11.0 | Flat Head | 5.0 – 5.1 |
| M4 | Round Body | 0.5 – 2.0 | 12.5 | Flat Head | 6.0 – 6.1 |
| M5 | Round Body | 0.5 – 3.0 | 14.0 | Flat Head | 7.0 – 7.1 |
| M6 | Round Body | 0.5 – 3.5 | 15.0 | Flat Head | 9.0 – 9.1 |
| M8 | Round Body | 0.8 – 4.0 | 17.0 | Flat Head | 11.0 – 11.1 |
| M10 | Round Body | 1.0 – 5.0 | 21.0 | Flat Head | 13.0 – 13.1 |
| M6 | Hex Body | 0.5 – 3.5 | 15.5 | Flat Head | 8.9 (hex hole) |
| M8 | Hex Body | 0.8 – 4.0 | 17.5 | Flat Head | 11.9 (hex hole) |
Grip range is a key parameter in rivet nut design. It refers to the range of material thickness that a rivet nut can securely clamp when installed. It is typically measured in millimeters (mm) or inches (inch) and directly affects installation performance and connection reliability.
1. Definition
The grip range defines the thickness of the workpiece material that the rivet nut can properly deform and firmly clamp during installation. If the actual material thickness falls outside of this range, the fastening may fail.
2. Example
- For instance, an M6 flat head rivet nut with a grip range of 0.5 – 3.0 mm means it is suitable for sheet thicknesses between 0.5mm and 3.0mm.
- If the sheet is only 0.3mm thick, the rivet nut may not grip securely.
- If the sheet is 4.0mm thick, the rivet nut may fail to fully deform, resulting in poor installation or failure.
3. Why Is Grip Range Important?
- Clamping Reliability: Using a rivet nut outside its grip range may lead to loosening, spinning, or thread damage.
- Structural Safety: Incorrect grip range selection reduces connection strength and may compromise structural integrity.
- Installation Efficiency: Proper grip range improves installation success rate and reduces rework.
- Selection Guide: Matching the grip range with the actual material thickness is essential when choosing rivet nuts.
How to Select the Right Grip Range？
When choosing a rivet nut, the grip range is one of the most critical parameters. Selecting the correct grip range ensures secure fastening, prevents loosening or failure, and enhances overall durability.
1. Base the Selection on Total Workpiece Thickness
- Use precision measuring tools such as calipers to accurately measure the total thickness of the installation area.
- For multilayer structures (e.g., two plates + coating + adhesive), sum all layers to calculate the total thickness.
- Example: If the top steel plate is 1.0mm, bottom aluminum plate is 1.2mm, and adhesive layer is 0.2mm, the total thickness is 2.4mm.
2. Avoid Using the Extreme Ends of the Grip Range
- Although a rivet nut may be rated for a grip range like “0.5–3.0mm,” it is not recommended to use it near the edges (e.g., 0.5mm or 3.0mm) regularly.
- Optimal performance is usually achieved in the mid-range, such as 1.5–2.5mm, where clamping force and deformation are most stable.
- Using edge values increases the risk of loose fastening or poor deformation due to thickness tolerance or installation variance.
3. Choose a Wider Grip Range for Variable Material Thickness
- In mass production, if the material thickness varies slightly (e.g., ±0.2mm), it’s better to select a wider grip range rivet nut for better tolerance.
- Wide-range nuts typically offer more deformation allowance, accommodating variations more easily.
- Example: If thickness may fluctuate between 1.6mm and 2.3mm, a 0.5–3.0mm grip range is safer than 1.5–2.5mm.
4. Different Rivet Nut Types Have Different Grip Range Sensitivities
- Open-end rivet nuts generally have more flexible deformation, and thus greater grip range adaptability.
- Closed-end rivet nuts, with a sealed tail, offer limited deformation, requiring tighter grip range precision.
- Specialized shapes like hex or knurled rivet nuts may also be more sensitive to grip range variations and should strictly follow the manufacturer’s specs.
Grip Range vs. Body Length
The Larger the Grip Range, the Longer the Body Length
- Rivet nuts require a certain amount of deformation during installation. The larger the grip range, the longer the body length needs to be to accommodate thicker materials and ensure proper clamping force.
- Example: For M6 rivet nuts, a model with a grip range of 0.5–3.0 mm will have a significantly shorter body than one with a 3.0–6.0 mm grip range.
Watch Out for Space Constraints
- When rear or internal installation space is limited, a longer body length may interfere with nearby structures or even prevent installation altogether. In such cases, prioritize rivet nuts with a shorter body or a reduced grip range.
- Recommended options include:
- Using small flange or flat head rivet nuts to minimize space usage;
- Choosing open-end rivet nuts, which are generally shorter than closed-end types;
- Selecting short-body versions designed for grip ranges below 2 mm.
Pro Tip: Measure Depth Before Installation
Before installation or during design, use a depth gauge or caliper to accurately measure the available depth of the installation area. Then compare it with the rivet nut’s body length to ensure it fits fully without binding or installation failure.
Consequences of Incorrect Installation
In practical applications, failing to select a rivet nut with the correct grip range to match the material thickness can seriously affect installation quality and connection reliability. Below are several common incorrect installation scenarios and their consequences:
Material Thickness Below Grip Range Minimum
- When the material thickness is less than the minimum specified grip range of the rivet nut, the nut cannot form a secure clamping zone in the material.
- Possible consequences include:
- Loose clamping, causing the rivet nut to spin during or after installation;
- Loosening or falling out under torque;
- Inadequate anti-loosening performance in environments with vibration.
Material Thickness Above Grip Range Maximum
- When the material thickness exceeds the maximum grip range, the rivet nut cannot deform properly during installation.
- This may result in:
- Poor fixation in the workpiece and unstable connections;
- Excessive force during installation causing the rivet nut body to crack or deform;
- Misalignment, thread stripping, or internal failure during bolt tightening.
Structural Risk and Torque Instability
- Incorrect grip range selection affects not only the individual rivet nut but may also compromise the entire structural integrity.
- Under high loads or in vibrating environments, torque values may fluctuate, increasing the risk of structural loosening and potential safety hazards.
Recommendation: Always select rivet nuts whose grip range falls within the middle range of your actual material thickness. Perform pre-installation clamping tests to ensure safe and stable fastening.
FAQs
1. Can I use a rivet nut outside its grip range?
It is not recommended to use a rivet nut outside its specified grip range. The grip range is the effective material thickness range determined by the manufacturer based on the rivet nut’s design and deformation capacity, ensuring the rivet nut can properly deform and securely clamp the material.
If the material thickness is less than the lower limit of the grip range, the rivet nut may not form sufficient deformation and clamping force, leading to “spinning” or loosening of the nut, resulting in an unstable connection. Conversely, if the material thickness exceeds the upper limit of the grip range, the rivet nut may not fully deform, which can cause the nut body to crack or fail to secure firmly, compromising the structural connection. Therefore, to ensure installation quality and structural safety, it is crucial to select and use rivet nuts strictly within their specified grip range and avoid the risks associated with using them outside this range.
2. How does grip range affect torque strength?
Grip range directly impacts the torque strength of a rivet nut connection. When a rivet nut is used within its specified grip range, it deforms properly to tightly clamp the material, providing optimal resistance to rotational forces. This secure deformation ensures that the rivet nut can withstand the intended torque without slipping or loosening.
If the grip range is too large or the rivet nut is used outside its recommended thickness range, the clamping force may be insufficient or uneven. For example:
- If the material is thinner than the minimum grip range, the rivet nut may not deform enough, causing it to spin inside the hole under torque, reducing the effective torque strength.
- If the material is thicker than the maximum grip range, the rivet nut may not fully collapse or deform properly, leading to a weak mechanical joint that can fail under torque.
In summary, using the correct grip range ensures stable clamping force and maximizes torque strength, while improper grip range selection risks joint failure due to insufficient torque resistance.
3. Is grip range the same for closed-end and open-end rivet nuts?
No, the grip range is generally not the same for closed-end and open-end rivet nuts, and this difference is important to consider when selecting the right rivet nut for your application.
- Closed-End Rivet Nuts: These have a sealed bottom, which prevents fluids, dust, or debris from entering the hollow interior. Due to their design, closed-end rivet nuts usually have a slightly narrower grip range because the material thickness must allow the rivet nut to deform properly without damaging the closed end.
- Open-End Rivet Nuts: These are open at the bottom, allowing for longer body lengths and sometimes a wider grip range. They can be used in applications where access through the hole is needed or when a longer grip range is required to accommodate thicker materials or stacked components.
In general, open-end rivet nuts tend to have a broader grip range compared to closed-end types, but the exact values depend on the manufacturer and specific model. Always refer to the product specifications to ensure the grip range fits your material thickness and installation needs.
4. What if I have stacked materials with varying thickness?
When dealing with stacked materials of varying thickness, selecting the right rivet nut grip range becomes more critical to ensure a secure and reliable fastening. Here are some detailed points to consider:
- Calculate Total Thickness: Add up the thicknesses of all stacked layers to determine the total material thickness that the rivet nut must clamp.
- Choose a Grip Range That Covers the Total Thickness: Select a rivet nut with a grip range that comfortably includes the combined thickness. Avoid choosing a grip range that’s too close to the minimum or maximum to prevent installation issues.
- Consider Material Variability: If the stacked materials vary in thickness between assemblies, choose a rivet nut with a wider grip range to accommodate these differences without compromising the joint strength.
- Use Shims or Spacers if Necessary: In some cases, adding shims can help adjust the overall thickness and improve grip if the rivet nut’s grip range is limited.
- Verify Installation Parameters: Test the rivet nut installation on sample stacks to ensure proper deformation and secure fastening without slipping or damage.
By carefully evaluating stacked thickness and selecting the appropriate grip range, you can achieve durable and stable connections even with complex material assemblies.
