Nut Insert Round Body CSK Flange Technical Datasheet
Open and Closed End
Product Overview
Nut Insert Round Body Countersunk (CSK) Flange provides a strong, reusable internal thread in thin sheet materials while allowing the flange to sit flush with the surface after installation. The countersunk head offers an aesthetically clean finish and eliminates protrusions, making these inserts suitable where surface flatness is essential.
This datasheet covers both Open End and Closed End variants, manufactured in Steel (Zinc Plated) and Stainless Steel, and provides dimensional data, technical specifications, material options, and application guidance for engineering and manufacturing applications.
Table of Contents
Standards
Manufacturers Standard
Installation
Dimensions
Open End Round Body CSK Flange Nut Insert
ITEM CODE: 4053
The Open End design allows screws or bolts to pass completely through the insert when required, making it suitable for assemblies where longer fasteners or through-hole engagement is needed.
| Size | Grip Range | A | Hole Size +0.1 | D +0.07, -0.1 | B | K | L |
|---|---|---|---|---|---|---|---|
| M3 – Gr 1 | 1.5-2.5 | 4.5 | 5 | 4.9 | 7.5 | 1.5 | 8.5 |
| M3 – Gr 2 | 2.5-4.0 | 10.5 | |||||
| M4 – Gr 1 | 1.3-3.0 | 6.5 | 6 | 5.9 | 9 | 1.5 | 12 |
| M4 – Gr 2 | 3.5-5.0 | 13 | |||||
| M5 – Gr 1 | 1.5-3.5 | 7.5 | 7 | 6.9 | 10 | 1.5 | 13 |
| M5 – Gr 2 | 3.0-5.0 | 15 | |||||
| M6 – Gr 1 | 1.5-4.0 | 9 | 9 | 8.9 | 12 | 1.5 | 15.5 |
| M6 – Gr 2 | 4.0-6.0 | 17 | |||||
| M8 – Gr 1 | 2.0-4.5 | 11 | 11 | 10.9 | 14 | 1.5 | 18.5 |
| M8 – Gr 2 | 4.5-6.0 | 19 | |||||
| M10 – Gr 1 | 2.0-5.0 | 13 | 13 | 12.9 | 16 | 1.5 | 21 |
| M10 – Gr 2 | 3.5-6.5 | 24 | |||||
| M12 – Gr 1 | 2.0-5.0 | 16.5 | 16 | 15.9 | 19 | 1.9 | 24 |
| M12 – Gr 2 | 5.0-7.0 | 24 |
Closed End Round Body CSK Flange Nut Insert
ITEM CODE: 4060
The Closed End design helps protect the internal thread from moisture, dust, oil and other contaminants while providing a clean finished appearance. Closed end inserts are commonly used in applications requiring environmental sealing, corrosion resistance or protection of internal components.
| Size | A | Hole Size +0.1 | D +0.07, -0.1 | B | K | L |
|---|---|---|---|---|---|---|
| M3 – Gr 1 | 10.3 | 5 | 4.9 | 7.5 | 1.5 | 15.5 |
| M3 – Gr 2 | 17.5 | |||||
| M4 – Gr 1 | 12.3 | 6 | 5.9 | 9 | 1.5 | 17.5 |
| M4 – Gr 2 | 19.5 | |||||
| M5 – Gr 1 | 14 | 7 | 6.9 | 10 | 1.5 | 19.5 |
| M5 – Gr 2 | 23.5 | |||||
| M6 – Gr 1 | 17.5 | 9 | 8.9 | 12 | 1.5 | 23.5 |
| M6 – Gr 2 | 25.5 | |||||
| M8 – Gr 1 | 20 | 11 | 10.9 | 14 | 1.5 | 26.5 |
| M8 – Gr 2 | 29.5 | |||||
| M10 – Gr 1 | 21.5 | 13 | 12.9 | 16 | 1.5 | 30 |
| M10 – Gr 2 | 32.5 | |||||
| M12 – Gr 1 | 22.5 | 16 | 15.9 | 19 | 1.9 | 33 |
| M12 – Gr 2 | 35 |
all dimensions in mm
Material Characteristics and Recommended Applications
| Material | Characteristics | Typical Applications |
|---|---|---|
| Steel Zinc Plated | High strength, economical, suitable for indoor environments | Industrial equipment, electrical panels, machinery |
| Stainless Steel A2 | Excellent corrosion resistance and strength | Food equipment, marine, outdoor enclosures, pharmaceutical machinery |
Technical Specifications
| Property | Specification |
|---|---|
| Product Type | Blind Rivet Nut |
| Body Style | Round Body |
| Flange Style | Countersunk (CSK) Flange |
| End Style | Open End / Closed End |
| Thread Type | ISO Metric |
| Thread Size | M3-M12 |
| Installation | Blind Installation |
| Material Options | Steel, Stainless Steel |
| Finish (Steel) | Zinc Plated |
| Finish (SS) | Plain Passivated |
| Installation Tool | Manual, Pneumatic, Hydraulic |
| Recommended Materials | Steel, Stainless Steel, Aluminium, Composite Panels |
Applications
- Sheet Metal Fabrication
- Electrical Control Panels & Enclosures
- Datacentres
- HVAC Equipment
- Telecommunications Cabinets
- Data Centre Infrastructure
- Automotive Components
- Commercial Vehicles
- Furniture Manufacturing
- White Goods & Appliances
- Signage
- Solar Equipment
- General Industrial Fabrication
Advantages
- Flush installation due to countersunk head
- Provides strong reusable threads in thin materials
- Suitable where a flat finished surface is required
- Blind installation from one side only
- Eliminates welding and tapping operations
- Quick and reliable installation
- Suitable for thin sheet metal and hollow sections
- Available in Open End and Closed End configurations
- Closed End version prevents ingress of dust, liquids and contaminants
- Compatible with manual, pneumatic and battery-powered installation tools
- Available in Steel and Stainless Steel
- Applications
Frequently Asked Questions
What is a CSK flange nut insert?
A CSK (Countersunk) flange nut insert is a blind rivet nut with a countersunk head that sits flush with the surface after installation, providing a clean appearance and reusable internal threads.
What is the difference between open end and closed end nut inserts?
Open end inserts allow screws to pass completely through the insert, while closed end inserts have a sealed bottom that prevents moisture, dust, and contaminants from entering the assembly.
When should I choose a countersunk flange instead of a large flange?
Countersunk flange inserts are used when a flush surface is required. Large flange inserts provide greater bearing area and are preferred where pull-out resistance is more important.
Can these nut inserts be installed from one side?
Yes. They are blind fasteners and require access from only one side of the workpiece.
What materials can these inserts be installed into?
They are commonly installed into steel, stainless steel, aluminium, and other ductile sheet materials.
Are they reusable?
Yes. The internal thread is designed for repeated assembly and disassembly.
Which installation tools are compatible?
Manual, battery-powered, pneumatic, and hydraulic rivet nut installation tools can all be used depending on production volume.
Need Technical Assistance or a Quote?
Looking for pricing, samples, CAD drawings, or help selecting the right fastener? Our team can help you choose the correct product for your application.
📧 sales@horizonincindia.com | 📞 +91 80 4117 9152 | 💬 +91 99167 77262
Related Products
Technical Disclaimer
The technical information, specifications, dimensions, mechanical properties, drawings, and performance data provided on this website are intended for general reference and engineering guidance only. Values shown are representative of products manufactured under normal production conditions and may vary depending on material grade, manufacturing tolerances, installation method, application, and operating environment.
While Horizon Inc. makes every reasonable effort to ensure the accuracy of the information provided, we make no warranties, express or implied, regarding its completeness, accuracy, or suitability for any particular purpose. Customers are responsible for verifying that the selected product is appropriate for their specific application and operating conditions. Where safety, structural integrity, or regulatory compliance is critical, independent engineering evaluation and product testing should be performed.
Horizon Inc. reserves the right to modify product specifications, dimensions, materials, and technical data without prior notice.
To the fullest extent permitted by applicable law, Horizon Inc. shall not be liable for any direct, indirect, incidental, consequential, or special damages arising from the use of, or reliance upon, the information contained on this website.
Copyright
© 2026 Horizon Inc. All Rights Reserved.
All content, product data, specifications, technical drawings, images, and documents published on this website are the property of Horizon Inc. and may not be reproduced, distributed, modified, or transmitted without prior written permission.
