In high-stakes industrial assembly, fastener ends require protection from structural and environmental threats, as well as an aesthetic, clean finish. Standard hex dome nuts often fail to accommodate significant bolt protrusions, leading to thread bottoming, structural gaps, or thread strip risks. As a specialized OEM High Crown Cap Nuts Supplier & Exporter, Sinsun Hardware addresses this challenge with our deep-dome design. These fasteners offer increased clearance for extended bolts, safeguarding connection points from rust, dust, physical impact, and operational wear.
Our High Crown Cap Nuts conform to major international standards like DIN 1587 and ASME B18.2.2. They are built to withstand high vibration and harsh outdoor settings. Sinsun's cap nuts feature a smooth dome dome finish (Ra ≤ 0.4μm) and deep internal threads. They help minimize the risk of thread jamming, providing a secure, reliable fit for demanding industrial applications.
Our deep dome cap nuts feature an extended internal cavity height. This extra vertical space accommodates longer thread protrusions without bottoming out. This design helps maintain reliable clamping force, even when bolt cuts vary in length.
We use automated cold heading and roll-threading to manufacture threads with precise tolerances (6H/6g classes). This clean threading minimizes binding risks and ensures smooth installation, even during high-speed automated assembly.
Our finishes feature a low roughness profile (Ra ≤ 0.4μm). This smooth surface prevents microbial buildup and minimizes friction during torque application, providing consistent preloads across heavy production runs.
| Metric Nominal Diameter | Thread Pitch (Coarse/Fine) | Total Dome Height (mm) | Across Flats Width (mm) | Min. Internal Thread Depth |
|---|---|---|---|---|
| M6 | 1.00 mm | 15.00 - 18.00 mm | 10.00 mm | 11.50 mm |
| M8 | 1.25 mm / 1.00 mm | 18.00 - 22.00 mm | 13.00 mm | 15.00 mm |
| M10 | 1.50 mm / 1.25 mm | 24.00 - 28.00 mm | 17.00 mm | 19.50 mm |
| M12 | 1.75 mm / 1.50 mm | 30.00 - 35.00 mm | 19.00 mm | 24.00 mm |
| M16 | 2.00 mm / 1.50 mm | 38.00 - 45.00 mm | 24.00 mm | 31.00 mm |
We source our raw steel directly from trusted manufacturers, including the Ansteel Group. We use premium cold-heading grade steel like C1022A, ensuring high quality from the very start. Sinsun manages the entire manufacturing process in-house, from spheroidizing annealing and wire drawing to cold heading, thread rolling, and final surface treatment.
Our facility runs four modern heat treatment lines, processing up to 20 tons daily. This integrated setup gives us precise control over product hardness (HRC 28-32) and helps us maintain stable, predictable lead times.
Total integrated facility footprint in Northern China's fastener hub.
Smart logistics center with 18,000+ pallet slots.
Annual shipment volume exported to key global markets.
Comprehensive inventory, including screws, nuts, bolts, nails, and rivets.
Industrial requirements are shifting toward lighter materials and enhanced corrosion resistance. Sinsun's research team is actively developing advanced surface coatings and alloys to meet these evolving needs:
Exposed chassis threads face road debris and corrosive salts. Sinsun's high crown cap nuts seal thread ends, preventing moisture intrusion and ensuring predictable disassembly for service.
Solar arrays and wind turbines require long-lasting, weather-resistant hardware. Our cap nuts, featuring 1000+ hour salt spray protection, help keep critical electrical and structural connections secure.
For offshore and marine applications, we supply SUS316 stainless steel cap nuts. These fasteners offer high resistance to pitting and crevice corrosion in harsh saltwater environments.
Our ERP-driven logistics tracking monitors every batch from raw wire drawing through heat treatment to shipping. This system ensures consistent quality and on-time deliveries, allowing us to maintain an on-time delivery rate exceeding 99%.
Our coatings, including zinc plating and Dacromet treatments, comply with RoHS directives. We exclude hexavalent chromium compounds to ensure safe use across global markets.
Every shipment is backed by material test reports (MTRs) detailing mechanical properties, alloy chemistry, hardness, and plating thickness to verify standard compliance.
Established manufacturing facility with a focus on self-tapping screws and core structural fasteners.
Expanded export operations to reach industrial buyers across Europe, the Middle East, and Latin America.
Integrated Taiwanese cold heading equipment and German-engineered multi-station production machinery.
Reaching an annual output of 36,000 tons, supported by a 12,000 sqm smart logistics center.
Challenge: A Tier-1 automotive supplier needed a custom flange bolt with high vibration resistance and weight reduction.
Sinsun Solution: We redesigned the component using a tailored alloy steel and added a specialized thread-locking feature, verifying performance through extensive stress testing.
Result: Achieved a 15% weight reduction, and the fasteners successfully passed 2,000-hour vibration testing for seamless integration into high-speed assembly lines.
Challenge: A marine engineering firm required large-diameter bolts with extreme corrosion resistance for a harsh saltwater environment.
Sinsun Solution: Recommended and supplied duplex stainless steel with a specialized passivation coating, backed by full heat-traceability and material certifications.
Result: Successful project completion with zero fastener failures, meeting the client's strict durability requirements.
We work directly with your team to analyze mechanical requirements, environmental factors, and dimensions, using 3D design previews before production.
Our engineers produce pre-production samples for physical and mechanical testing, ensuring all specs match your requirements.
Production runs on German-imported cold headers and Taiwanese roll threaders, with 12+ strict quality checks at key stages.
SINSUN
