How 18 Years of Cold Forging Mastery and Automated Washer Assembly Ensures Zero-Drop, Streamlined Fastening for Industrial Clients

•   The Cold Forging Foundation: Strength Begins at the Grain Level

At our production facility, every combination screw begins with precision cold forging. Unlike turned or cut screws, cold forging compresses the steel at room temperature, forcing the metal grain flow to follow the contour of the head and the thread flanks. This results in a screw with superior tensile and shear strength. As an 18-year manufacturer, we know that the integrity of a combination screw is not just about the washer—it's about the uninterrupted grain structure of the core fastener. This is the foundation that allows our products to consistently meet the ASTM, BS, and AS standards demanded by our UK, US, and Australian partners.

•  Automated Washer Assembly: The Precision of Captive Integration

The defining feature of a combination screw (also known as a SEMS screw) is that the washer is permanently captured onto the shank during the manufacturing process. At our facility, this is achieved through high-speed automated assembly lines that precisely feed and press flat or spring washers onto the screw blank before thread rolling. The washer ID is engineered slightly smaller than the major thread diameter, ensuring it rotates freely but cannot be removed. This captive design eliminates the risk of lost washers during transport and installation—a critical efficiency factor for US and UK assembly lines where dropped components cause costly downtime.

•  Thread Rolling Precision: Post-Assembly Integrity

The thread rolling process is where true production expertise shows. At [Your Company Name], we perform thread rolling only after the washer is assembled onto the blank. This ensures that the washer is permanently trapped behind the full-profile threads. Our precision rolling dies create clean, sharp threads with exact pitch tolerance, minimizing the risk of cross-threading during customer installation. For our Australian and UK partners in the electronics and automotive sectors, this post-assembly rolling process guarantees that every combination screw meets full thread engagement specifications without damaging the pre-attached washer.

•  Quality Control and Surface Treatment: The Final Production Mile

Production quality is validated through rigorous inspection. Our QC process employs automated optical sorting machines to check for washer integrity, thread form, and dimensional accuracy at high speed. Any component showing washer misalignment, incomplete thread formation, or surface defects is automatically rejected. Following inspection, our in-house plating lines apply uniform Zinc, Zinc-Nickel, or Ruspert coatings, precisely controlled for thickness to guarantee salt spray resistance. For our global export markets, every batch is traceable back to the raw material heat number, providing the documentation chain that professional procurement teams demand.

•  About Us

With 18 years of integrated manufacturing and global trade expertise,Nantong  JINDI FASTENER CO.,LTD  is a leading provider of high-performance fastener solutions. Exporting 95% of our production to the UK, USA, and Australia, we specialize in delivering the precision and quality that industrial assembly demands. By combining in-house cold forging, automated assembly, and rigorous quality control, we provide our procurement partners with fasteners that reduce assembly costs and increase product reliability.