introduction to products：
Black Zinc/Black Oxide DIN7340 Knurled Blind Rivet Nuts are cylindrical fasteners with knurled outer walls and internal threads. Crafted from carbon steel (available in strength grades 4.8, 8.8, 10.9), black zinc plating offers corrosion resistance (ideal for damp environments), while black oxide coating enhances wear resistance (suited for high - friction scenarios). The knurled design ensures a firm grip on thin workpieces (such as sheet metal and hollow tubes), enabling blind - side installation (no need for back - side access) to add internal threads to thin materials. Compliant with the DIN7340 standard, they come in metric sizes ranging from M3 to M12 and are widely used in metalworking, sheet metal fabrication, automotive body panel mounts, furniture frame assembly, and light - duty structural connections.
Instructions for Use：
First, drill a hole in the workpiece with a diameter matching the rivet nut (for example, an M6 nut requires a 6mm - compatible hole). Insert the nut into the hole and then use a dedicated rivet tool (either manual or pneumatic) to pull it, causing the knurled wall to embed into the material. Regularly check the knurling for signs of wear (replace the nut if slipping occurs). For black zinc - plated nuts, repair any scratches with anti - rust paint. For black oxide - coated nuts, clean them regularly to maintain their wear - resistant properties.
| Nominal Diameter | 3 | 4 | 5 | 6 | 8 | 10 | |
| d | |||||||
| d | max=nominal size (h13) | 3 | 4 | 5 | 6 | 8 | 10 |
| min | 2.86 | 3.82 | 4.82 | 5.82 | 7.78 | 9.78 | |
| d2 | max=nominal size | 5.5 | 7.5 | 9.5 | 11.5 | 15.5 | 18 |
| min | 5.2 | 6.92 | 8.92 | 10.8 | 14.8 | 17.3 | |
| d3 | min | 2.85 | 3.8 | 4.8 | 5.8 | 7.75 | 9.75 |
| d0 | max=nominal size | 1.66 | 2.62 | 3.42 | 4.12 | 5.18 | 7.18 |
| min | 1.26 | 2.22 | 3.02 | 3.72 | 4.78 | 6.78 | |
| e | max | 1.5 | 2 | 2.5 | 3 | 4 | 5 |
| k | max | 0.8 | 1 | 1 | 1.2 | 1.2 | 1.4 |
| min | 0.6 | 0.8 | 0.8 | 1 | 1 | 1.2 | |
| r | max | 0.2 | 0.3 | 0.3 | 0.4 | 0.4 | 0.6 |
| s | Nominal Size | 0.5 | 0.5 | 0.6 | 0.75 | 1.2 | 1.2 |
| max | 0.6 | 0.6 | 0.7 | 0.85 | 1.3 | 1.3 | |
| min | 0.4 | 0.4 | 0.5 | 0.65 | 1.1 | 1.1 | |
| s1 | min | 0.4 | 0.4 | 0.5 | 0.6 | 1 | 1 |
| Weight of per 1000 steel products(≈kg) | - | - | - | - | - | - | |
Hebei Duojia Metal Products Co., Ltd. was formerly known as Yonghong Expansion Screw Factory. It has over 25 years of professional experience in manufacturing fasteners. The factory is located in the China Standard Room Industrial Base - Yongnan District, Handan City. It conducts online and offline production and manufacturing of fasteners as well as one-stop sales service business.
The factory covers an area of over 5,000 square meters, and the warehouse covers an area of over 2,000 square meters. In 2022, the company carried out industrial upgrading, standardized the production order of the factory, improved the storage capacity, enhanced safety production capacity, and implemented environmental protection measures. The factory has achieved a preliminary green and environmentally friendly production environment.
The company has cold pressing machines, stamping machines, tapping machines, threading machines, forming machines, spring machines, crimping machines, and welding robots. Its main products are a series of expansion screws known as "wall climbers".
It also produces special-shaped hook products such as wood tooth welding sheep eye ring screws and machine tooth sheep eye ring bolts. In addition, the company has expanded new product types from the end of 2024. It focuses on pre-buried products for the construction industry.
The company has a professional sales team and a professional follow-up team to safeguard your products. The company guarantees the quality of the products it offers and can conduct inspections on the grades. If there are any problems, the company can provide professional after-sales service.
Our export countries include Russia, South Korea, Britain, France, Germany, Italy, Canada, Mexico,Brazil, Argentina, Chile, Australia, Indonesia, Thailand, Singapore, Saudi Arabia, Syria, Egypt, Tanzania.Kenya and other countries. Our products will be spread all over the world!
WHY CHOOSE US?
1.As a factory-direct upplier,we eliminate middleman margis to offer you the most competitive pricing for high-quality fasteners.
2.our factory pass the ISO 9001 and AAA certification .we have the hardness testing and the test of zinc coating thickness for galvanized products.
3.with full contrl over production and logistic,we guarantee on-time delivery even for urgnt orders .
4.our engineering team can customize faseners from prototype to mass production , including unique thread designs and anti-corrosion coatings.
5.From carbon steel hex bolts to high-tensile anchor bolts ,we provide a one-stop solution for all your fastener needs.
6.If any defect is found ,we’ll reship replacements within 3weeks of our cost .
