Ningyuan Fastener
Ningyuan Fastener
Engineered standard components and specialized anchors optimized for high-tensile load applications.
In heavy structural engineering, architectural joining, and modular industrial installations, the integrity of a fastening system determines structural longevity. The Double Threaded Screw (commonly referred to as a dowel screw or dual-thread stud) is a highly specialized mechanical fastener designed to facilitate seamless transitions between distinct structural components. Engineered with thread profiles on both opposing ends, these fasteners play a critical role in anchoring wood structures to steel substrates, fixing structural brackets in solar photovoltaic installations, and supporting seismic mechanical, electrical, and plumbing (MEP) systems.
Unlike standard single-axis screws, double threaded configurations leverage unique thread designs. Typically, one end features a coarse, deep wood thread (designed to maximize pull-out resistance in timber or concrete plugs), while the opposite end features a metric or unified national fine (UNF) machine thread designed to accept nuts, structural brackets, or steel channel couplers. Understanding the mechanical stress distributions, material compositions, and manufacturing pathways of these components is vital for global procurement teams and structural engineers alike.
Dual pitch dynamics balance the holding power of wood/dowel thread profiles with the precision torque capacity of machine threads, preventing failure under cyclical loads.
Engineered with protective barrier layers, including Hot-Dip Galvanizing (HDG) and Dacromet, to guarantee decades of reliability in harsh C4/C5 marine settings.
Facilitates transitions in complex assemblies, bridging the gap between heavy structural steel framework and wood-based structural elements.
Established in 2005 (originally operational as the Jin Langtao brand), Handan Ningyuan Fastener Manufacturing Co., Ltd. is located in Yongnian, Handan, widely recognized as the global fastener manufacturing capital. Over 18 years of focused engineering refinement, the company has grown from a specialized fastener workshop into a modernized manufacturing enterprise integrated across R&D, advanced material cold-forming, precise heat treatment, surface finishing, and global distribution operations.
Covering an expansive factory footprint of 20,000 square meters, our production floors house over 50 sets of advanced manufacturing machinery. Driven by a dedicated engineering and quality assurance team, Ningyuan produces high-performance fastening systems for new energy photovoltaic systems, seismic support assemblies, integrated underground utility pipelines, and high-strength industrial structures.
Our expert engineers are available to review your custom requirements.
Double threaded screws act as key load-bearing anchors across modern infrastructure sectors. By isolating load transitions, they prevent structural fatigue at wood-to-metal and concrete-to-steel boundaries. Below are the primary macro-industry applications where double threaded fasteners are essential.
In solar mounting systems, solar hanger bolts (a prominent class of double threaded screws) secure structural aluminum or steel C-channels to wooden rafters or metal purlins. The wood-thread section embeds deep into the building frame, while the extended metric machine thread rises above the roofing material. This ensures structural stability for solar panel configurations subjected to wind uplift forces while maintaining roof water tightness via integrated EPDM washers.
Modern building codes mandate resilient seismic bracing for mechanical, electrical, and plumbing (MEP) systems. Double threaded connectors link structural concrete anchors to hanging threaded rods. These rods support heavy cable trays, HVAC ducts, and fluid piping, maintaining structural integrity under dynamic seismic loads and preventing system failures during natural disasters.
Engineered timber structures rely on double threaded dowel screws to create high-strength, concealed timber-to-timber and timber-to-steel joints. By embedding the threads completely within the wood fibers, structural engineers protect the steel fasteners from fire exposure and achieve a clean architectural aesthetic without compromising load-bearing capacity.
Selecting the correct material and surface coating is critical to ensuring the longevity of double threaded systems in corrosive environments. We produce fasteners in various carbon and stainless steels, custom-tailored to project specification requirements.
| Material Class | Common Grades | Tensile Strength (MPa) | Yield Strength (MPa) | Recommended Applications |
|---|---|---|---|---|
| Carbon Steel | Class 4.8 / 8.8 / 10.9 | 400 - 1040 | 320 - 940 | Standard solar mounting, indoor structural framing, HVAC hangers |
| Stainless Steel | SUS304 / SUS316 / A2 / A4 | 500 - 800 | 200 - 600 | Coastal solar arrays, chemical processing plants, marine installations |
| Alloy Steel | SCM435 / 40Cr | ≥ 1000 | ≥ 900 | High-stress seismic couplers, heavy machinery, automotive assemblies |
For outdoor and industrial service environments, untreated carbon steel is prone to rapid oxidation. Our facility utilizes advanced surface engineering treatments to extend fastener lifespan:
Our manufacturing facility in Handan Yongnian sits at the center of the world's largest fastener production network. This industrial concentration provides distinct supply chain advantages that we pass directly to our international clients.
Direct partnerships with regional steel mills ensure a reliable, continuous supply of premium steel rod coils, stabilizing production timelines even during volatile market cycles.
Yongnian's specialized industrial zone features shared modern facilities for hot-dip galvanizing, heat treatment, and surface coating, reducing lead times and transportation overhead.
Close proximity to Qingdao and Tianjin ports ensures streamlined container loading, rapid customs clearance, and cost-effective shipping to global industrial hubs.
At Handan Ningyuan Fastener, we operate under a strict quality management system to ensure that every double threaded screw meets rigorous international standards. Our manufacturing and testing processes comply with standard regulatory frameworks, including ISO9001 and ROHS EU testing.
Our QA laboratories monitor every batch of raw steel from input through cold heading, thread rolling, heat treatment, surface plating, and final dispatch. We perform systematic testing to ensure that our structural components perform reliably under high-stress conditions.
Consult this operational guideline to align fastener specifications with your local installation environments and mechanical load requirements.
Stainless Steel SUS316 with high acid/saltwater resistance. EPDM sealing washers prevent galvanic corrosion between aluminum rails and steel fasteners.
Grade 8.8 or 10.9 high-tensile carbon steel, hot-dip galvanized. Designed to withstand shear force spikes during seismic events.
Heavy-duty hot-dip galvanized double threaded rods. Capable of resisting continuous high-humidity environments and soil chemistry exposure.
Coarse wood thread profile coupled with metric fine threads. Engineered to prevent timber splitting while maintaining structural clamping force.
As global industries demand greater structural traceability and smarter installation processes, the technology behind simple fasteners is rapidly evolving. At Handan Ningyuan, we are continually upgrading our manufacturing capabilities to align with these emerging global trends.
Modern mega-structures, such as offshore wind farms and long-span suspension bridges, increasingly use fasteners embedded with micro-strain sensors. These smart fasteners monitor tension levels in real-time, allowing operators to detect fatigue and bolt loosening before structural failure occurs.
To comply with stringent EU environmental regulations (such as RoHS and REACH), our R&D team is developing advanced chromium-free coatings. These new finishes match the corrosion resistance of traditional chemical treatments while minimizing environmental impact.
To reduce material waste and increase production efficiency, we are transitioning our high-volume production lines to multi-station cold-heading machines. This allows us to manufacture complex double threaded designs with high dimensional consistency and minimal scrap material.
High-precision structural components produced at our ISO9001 certified manufacturing facilities.
In-depth answers to key technical questions from engineers and procurement teams.
Whether you require standard double threaded screws or custom-engineered fasteners, our technical team is here to assist. Contact us today to request a quote, submit technical drawings, or request free product samples.
Manufacturer: Handan Ningyuan Fastener Manufacturing Co., Ltd.
Production Center: Yongnian District, Handan City, Hebei Province, China
Service Focus: Photovoltaic mounting hardware, seismic supports, steel construction bolts, and custom high-strength fasteners.
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