Explore our diverse portfolio of certified industrial fasteners engineered to match the highest quality standards worldwide.
The Largest Self Tapping Screw Production Base in Northern China & Premier Custom OEM Washer Factory
Sinsun Hardware, established in 2006, is a leading manufacturer and global supplier of high-quality fasteners. As Northern China's largest producer of Self-Tapping Screws, we operate from a gigantic 30,000 sqm integrated facility that includes modern production zones, a 12,000 sqm smart warehouse (18,000+ pallet capacity), and multi-language customer support centres. Our yearly supply of over 8,500 containers consistently services key global markets such as the Middle East, Southeast Asia, South America, and Russia. We bring this absolute manufacturing scale, rigorous quality standard, and supply reliability to our OEM Fender Washers production, serving high-volume industrial clients with tailored engineering solutions.
Why load distribution and precision sizing matter in heavy industrial assemblies.
A Fender Washer differs fundamentally from standard flat washers due to its disproportionately large outer diameter (OD) relative to its inner diameter (ID). Originally designed to secure automotive fenders, these specialized washers have evolved into critical fastening components across multiple industries—including construction, marine engineering, solar mounting structures, automotive panels, and drywall installations.
In structural assemblies, applying torque to a bolt or screw creates immense compressive force. When mating surfaces are soft (such as sheet metal, plastics, composites, or wood), standard washers may cause local yielding, crushing, or pull-through. Fender washers prevent this by dispersing the tightening force over a significantly broader surface area, thereby minimizing stress concentrations. This is mathematically defined as:
By increasing the outer diameter, the contact area increases exponentially, dramatically reducing average pressure (P_avg). For OEM applications, achieving exact specifications—where thickness, inner clearance, and outer profiles are tailored to the assembly’s material threshold—is vital to prevent mechanical failure, galvanic corrosion, or joint relaxation.
We manufacture custom fender washers according to international industrial specifications including DIN 9021, DIN 440, ISO 7093, and ASTM F436, ensuring accurate thickness, internal clearances, and dimensional tolerances of ±0.02mm.
Our raw material feedstock sourced directly from premier steelmakers (Xingtai Steel) features grades ranging from low-carbon and high-tensile steels to premium corrosion-resistant alloys (SS304, SS316) and structural brass.
Our stamping technology facilitates clean edge profiles (Ra ≤ 0.4µm) and versatile coating options including heavy-duty hot-dip galvanization, passivated zinc, Dacromet, and Geomet coatings exceeding 1,000 hours of salt spray testing.
Achieving mechanical integrity and high yield strength through vertically integrated production.
At SINSUN, our quality control begins at the source. We start with premium raw materials from XING TAI Steel, then perform in-house spheroidizing annealing and precision wire drawing in our own plant. This end-to-end control, supported by our advanced drawing machines and gas-fired furnaces, ensures superior microstructure, consistency, and performance in every fastener we produce. By processing steel wire rod coils ourselves, we can guarantee consistent grain structure—which is absolutely vital during the punch-stamping and forming of large-diameter washers to avoid edge micro-cracking and mechanical stress failures.
At SINSUN, we combine German-engineered multi-station cold heading machines with precision Taiwanese production technology. Our specialized processes, including tail-gripping for drill screws, ensure every fastener is manufactured with utmost accuracy and consistency in our state-of-the-art production facility. This technological foundation gives us the capacity to scale up stamping lines for high-volume custom fender washers, delivering consistent flatness and edge profiles across large production batches.
SINSUN operates four dedicated heat treatment lines, allowing for precise and controlled processing time to achieve consistent hardness and enhanced product durability. This in-house capacity ensures both exceptional fastener quality and reliable delivery schedules. See our advanced heat treatment systems in action, supporting our end-to-end manufacturing control. Heat treatment avoids hydrogen embrittlement in high-strength carbon steel washers, securing long-term reliability under severe dynamic preloads.
Addressing modern structural supply challenges with risk-mitigating options.
Our long-term procurement frameworks with premier domestic steel mills guarantee stable metal raw materials indexing, buffering B2B supply channels from sudden geopolitical fluctuations and commodity spikes.
Leveraging our 12,000 m² smart warehouse (holding an 18,000+ pallet capacity) and dedicated container planning, SINSUN guarantees consistent distribution timelines and eliminates transit bottlenecks for standard or custom orders.
All OEM stamping runs are supplied with MTRs (Mill Test Reports), mechanical test certificates, dimensional checklists, and complete packaging optimization details, supporting internal enterprise risk auditing.
From Sinsun founding in 2006, Sinsun has grown into a leading Chinese fastener manufacturer. Explore our journey of expansion.
Sinsun began with a singular focus in 2006: to build a factory dedicated to self-tapping screws. This foundational specialization established our core expertise from the ground up. It remains the unwavering commitment behind every screw and fastener we manufacture today.
The year 2012 marked a pivotal step for Sinsun with the establishment of our Export Department. From that point forward, our specialized fasteners and structural washers began reaching customers across the world, expanding our mission beyond borders.
In 2015, Sinsun expanded its control over quality by adding four spheroidizing furnaces for raw material processing and in-house wire drawing capabilities. This strategic upgrade moved our production beyond basic fastener forming, establishing quality control directly from the raw material stage.
Our production capability was enhanced in 2018 with new German multi-station cold heading machines. Concurrently, we grew our product line to include a variety of drill tail screws. This dual development strengthened our specialized manufacturing foundation.
Sinsun's growth in 2021 was defined by two key metrics: reaching 36,000 tons in annual production and fulfilling international orders with over 1,100 export containers. This period underscored our capacity to deliver at scale to a global market.
To ensure timely delivery for our clients, we operate an integrated 12,000 m² smart warehouse. This facility is dedicated to supporting efficient daily distribution and meeting your routine and emergency supply needs.
The addition of four heat treatment lines in 2025 significantly boosts our production capacity. This directly translates to greater consistency in product quality and stronger guarantees for on-schedule delivery, meeting your project needs with confidence.
How Fender Washers support structural safety in high-growth industrial sectors.
In solar panel installations, fastening brackets to thin metal roofing requires massive clamping area to resist dynamic wind uplift forces. Customized OEM fender washers protect the structure and distribute the load, mitigating localized deformation.
The rise of Electric Vehicles requires joining dissimilar materials, like aluminum panels to carbon composites. Specially coated fender washers distribute structural preloads, preventing composite crushing and galvanic corrosion.
Modern building designs demand fasteners to last decades. Sinsun's carbon and stainless steel washer options with advanced barrier coatings conform to ESG initiatives by eliminating structural degradation hazards.
Seamless custom solutions backed by professional design packaging and client collaboration.
SINSUN offers flexible OEM and ODM packaging tailored to your needs. With a professional packaging team and a 12,000 m² warehouse, we provide custom packaging, 3D design previews, and full logistics support to deliver a seamless, worry-free experience from production to shipment. Every month, we welcome clients from across the country for on-site factory visits, demonstrating our transparency and production strength. As a trusted industry partner, we actively participate in global exhibitions to connect, exchange insights, and showcase innovation — building lasting relationships based on quality and reliability.
Furthermore, our compliance protocols adhere to rigorous chemical standard limits. Our products undergo third-party chemical validation verifying complete adherence to RoHS (Restriction of Hazardous Substances) and REACH compliance guidelines, ensuring safe deployability in environmentally sensitive sectors.
Innovating the next generation of smart manufacturing and anti-corrosive fasteners.
As the industrial fastener sector shifts towards automation, green steel, and higher performance requirements, SINSUN is actively implementing its next-generation technology roadmaps:
Technical clarifications straight from our engineering department.
Typically, standard washers maintain a proportional ratio of about 2:1 for outer-to-inner diameter. A fender washer features an OD that is 3 to 4 times the size of the inner hole. In OEM production, SINSUN designs tools to maintain this ratio safely without compromising flatness or creating thinning margins near the inner aperture.
Large-diameter stamping is prone to internal residual stresses which trigger warping. By utilizing raw materials processed in-house via controlled spheroidizing annealing, we optimize uniform grain direction. This control, combined with calibrated progressive stamping presses, ensures that flatness tolerances are maintained across high-volume production runs.
For standard atmospheric applications, hot-dip galvanization is highly effective. However, for precision marine or high-vibration applications, SINSUN recommends Dacromet or Geomet zinc-flake barrier coatings. They prevent hydrogen embrittlement during application, stay thin (typically 5-15 microns) to maintain design dimensional clearances, and survive over 1,000 hours of salt spray exposure.
For custom sizing requiring unique stamping dies, tooling design and prototype approval takes 10 to 15 days. Upon tooling sign-off, high-volume production matches standard lead times, supported by our 12,000 m² smart warehouse to maintain buffer stocks for key accounts.
Yes, our packaging department supports complete customization, including bulk carton runs, custom small bags, visual retail packaging, and barcoded inventory boxes, allowing items to transition straight to your assembly line or retail floor.
Every batch goes through 12+ stringent quality checks including dimensional inspection via digital projectors, hardness tests (HRC 28-32), microstructure evaluation, plating thickness checks, and salt-spray testing, backed by detailed quality reports.
Discover more high-performance fasteners designed to optimize your industrial structural systems.
