Carriage Bolt (DIN 603) | Round Head Square Neck Bolt
Product Overview
The Carriage Bolt (DIN 603), also known as a Coach Bolt, features a smooth mushroom head and a square neck underneath. The square neck locks into the wood or a square hole in metal, preventing the bolt from rotating during tightening.
Designed for safety and security, the smooth head leaves no grip for tools to loosen it from the outside, making it ideal for fencing, timber construction, and playground equipment.
Key Features
Square Neck: Self-locking design prevents rotation when the nut is tightened.
Smooth Head: Round mushroom head provides a clean, aesthetic finish and enhanced security.
Versatile Material: Available in Carbon Steel (Galvanized) for strength or Stainless Steel for rust resistance.
Wide Application: Perfect for connecting wood-to-wood or wood-to-metal structures.
Technical Specifications
| Property | Specification |
| Product Name | Carriage Bolt / Round Head Square Neck Bolt |
| Standard | DIN 603, ISO 8677, ANSI B18.5 |
| Material | Carbon Steel, Stainless Steel (304/316) |
| Grade | Class 4.8, 8.8, 10.9 |
| Finish | Zinc Plated (Clear/Yellow), Black, Plain, Chrome |
| Head Style | Mushroom Head / Round Head |
| Size Range | M5 - M20 (Length: 20mm - 200mm) |
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Email: admin@changhua-electrical.com | WhatsApp: +86 181 3296 8158
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Manufacturing & Quality Control
 Advanced Cold HeadingPrecision manufacturing. |  Optical Sorting 0-PPM defects. |  Lab Testing Tensile & Salt Spray. |
Project References
 Interior Decoration (USA) Hanging Heavy Fixtures |  Ceiling System (Europe) Light Fixture Support |  Automotive (Germany) High Strength Fasteners |
Frequently Asked Questions
Q: Can I get free samples?
Yes! We provide free samples for standard fasteners. You only need to cover the shipping cost.
Q: What standards and MOQ do you support?
Mainly DIN 603 and ANSI B18.5. MOQ is flexible (500 kgs/1000 pcs) for standard items.
Q: What certifications do you have?
We are CE Certified. Every shipment comes with a Factory Quality Inspection Report.
Q: What is your delivery time?
Stock items: 3-7 days. Mass production: 20-30 days.
Q: Can you produce according to drawings?
Yes, OEM/ODM is our strength. Send us CAD drawings for a quote within 24 hours.
Q: What are your payment terms?
We generally accept T/T (30% deposit, 70% before shipment). For long-term partners, we can discuss L/C.
Interested in this product?
Get in touch for more information, pricing, or custom requirements.