Engineered for structural rigidity and peak performance under dynamic load distributions.
Established in 2006, Sinsun Hardware is a premier global manufacturer and direct supplier of high-integrity fasteners. Operating as Northern China's largest production facility of self-tapping screws and lock washers, our state-of-the-art manufacturing campus spans over 30,000 square meters. By integrating advanced production zones, a smart 12,000 square meter logistics center capable of holding 18,000+ pallets, and multiple language customer care facilities, we ship over 8,500 containers annually to structural, electronics, automotive, and retail markets worldwide.
Integrated manufacturing and specialized drawing facilities designed to house vertical production pipelines.
A comprehensive inventory range spanning custom external tooth lock washers, concrete screws, masonry anchors, coil nails, and custom electrical terminals.
Over 12 stages of quality testing including dimensional accuracy tolerances of ±0.02mm and salt-spray validation exceeding 1,000 hours.
How structural tooth profiles mitigate vibrational loosening under high-load applications.
External tooth lock washers (often referred to as star washers) are specialized mechanical fasteners designed to prevent threaded assemblies from backing out. Unlike traditional spring washers that rely solely on tension forces, external tooth washers employ a mechanical locking system. The outer perimeter contains teeth that are twisted outward to form a series of sharp edges.
When a nut or bolt is tightened down, these teeth bite into the mating surfaces—specifically the bolt head, nut, and joint material. This tooth indentation provides several engineering advantages:
External tooth lock washers are typically chosen when the bolt head diameter is wide, as they maximize locking efficiency at the outermost edge. Internal tooth lock washers are preferred for smaller bolt heads or instances where aesthetics demand the locking teeth remain hidden.
| Lock Washer Category | Torque Retention | Contact Surface Area | Primary Industry Applications |
|---|---|---|---|
| External Tooth | High (External dynamic friction) | Large outer diameter interface | Automotive panels, ground connections, structures |
| Internal Tooth | Medium-High (Internal radial friction) | Small localized internal diameter | Electronics assemblies, instrument cases |
| Standard Helical Split | Medium (Tension rebound force) | Uniform circular contact | Light mechanical clamping |
Explore our journey of strategic industrial expansion since 2006.
Sinsun set out with a singular, clear focus: establishing a specialized manufacturing base for self-tapping screws and precision washers, laying down our engineering foundations.
We established our dedicated Export Department, allowing our high-strength lock washers and threaded hardware to supply distributors and structural projects worldwide.
Sinsun integrated four spheroidizing annealing furnaces and high-precision wire-drawing lines, securing total control over fastener performance from the raw wire stage.
We imported German multi-station cold heading machines and upgraded our tooling lines to offer specialized drill tail designs and complex tooth washers.
Annual production scaled to 36,000 metric tons, enabling Sinsun to complete and ship over 1,100 international containers in a single calendar year.
Inaugurated a dedicated 1,200 square meter rapid-fulfillment warehouse, guaranteeing key fastener components are kept in stock for standard distributions.
Integrated four new automated heat treatment lines to increase output capacity, ensure consistent HRC hardness profiles, and secure quick order turnarounds.
At Sinsun, control begins at the source. We select premium steel coils from top Chinese mills like Xingtai Steel. Inside our facility, this steel undergoes in-house spheroidizing annealing, chemical pickling, and wire drawing. Employing Taiwanese cold heading setups and advanced German multi-station equipment, we forge lock washers and screws to precise geometries before they undergo our specialized heat-treatment lines.
Our four continuous heat treatment lines precisely manage annealing, hardening, and tempering. This achieves an ideal core hardness of HRC 28-32, maximizing washer flexibility without risking brittle failure.
We provide hot-dip galvanizing, mechanical plating, zinc-flake coating, and standard electroplating. Our treated washers survive salt spray tests for over 1,000 hours, meeting demanding outdoor and automotive standards.
Using Taiwanese tooling and optical sorting machinery, we verify external teeth profiles down to ±0.02mm, ensuring tight fits and proper torque performance in automated assembly setups.
Tailored fastening setups for harsh operating environments.
External tooth lock washers are critical across industries where vibration or thermal cycles can compromise joint integrity. Sinsun works closely with engineering teams to match washer specifications to their specific environments:
Under-hood components, chassis assemblies, and steering linkages face constant vibration. Our high-tensile carbon steel external tooth washers (HRC 40-50 after heat treatment) maintain bolt preload over long periods.
Electrical grounding terminals require consistent metal-to-metal connection. The teeth on our washers bite through paints and oxides, keeping circuit paths clear and preventing resistance build-up.
Outdoor racking systems face high winds and thermal expansion. Sinsun's SS316 stainless steel lock washers offer durable, corrosion-resistant locking that eliminates the need for frequent maintenance.
Leveraging intelligent logistics and automated production to ensure reliable delivery schedules.
Sinsun Hardware has transformed its operations by adopting modern industrial practices. Our 12,000 square meter smart warehouse handles inventory with automated sorting, tracking stock from initial manufacturing to final shipment container loading.
This system helps us balance high-volume production with custom manufacturing runs. By keeping raw materials processed in-house, we reduce the lead-time volatility that often affects other component suppliers.
Containers Shipped Annually
Pallet Capacity in Smart Warehouse
Strict Testing Protocols per Batch
Developing high-strength materials and smart coatings for demanding industrial applications.
Modern applications require high-strength, lightweight materials. Sinsun is testing titanium-alloy and high-entropy alloy lock washers. These materials reduce overall weight while providing excellent tension retention for aerospace and defense installations.
In response to changing environmental standards, we are shifting away from traditional hexavalent chromium coatings. Sinsun is adopting advanced, water-based zinc flake coatings that provide excellent corrosion resistance without hazardous byproducts.
As automated assembly systems become more common, lock washers must be feed-optimized. We are updating our tooth angles to prevent washers from nesting or tangling in bowl feeders, helping customers improve their assembly line speeds.
Meeting international quality benchmarks to ensure reliable on-site performance.
At Sinsun, we ensure our products meet key industry specifications. Our washers are designed, manufactured, and verified against major international standards, including:
Our technical team supports projects from design through to manufacturing. We help clients select appropriate materials, optimize dimensions, and perform 3D model checks to ensure custom fastener orders match exact system drawings.
Technical answers to common questions about selection, installation, and performance.
An inside look at our production floor, logistics areas, and quality control labs.
Selected high-strength anchors, structural concrete screws, and spring washers.
