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Author: Site Editor Publish Time: 2025-10-27 Origin: Site
A stainless steel carriage bolt, also known as a round head square neck bolt, is one of the most commonly used fasteners in construction, furniture, and machinery. With its unique design — a rounded head and square neck — this bolt provides a strong, smooth, and tamper-resistant connection.
Carriage bolts are especially popular in wood-to-metal or wood-to-wood connections, offering a clean appearance and excellent performance in both indoor and outdoor applications.
A carriage bolt features a domed (round) head with a square section beneath it. The square neck locks the bolt in place once inserted into a square hole or wood surface, preventing rotation during tightening.
Made of high-quality stainless steel, this bolt provides superior corrosion resistance and mechanical strength, making it perfect for long-term use in harsh environments.
| Feature | Description |
|---|---|
| Material | Stainless steel (A2-70 / A4-80) for excellent rust resistance |
| Head Type | Round or dome-shaped head for a smooth, aesthetic surface |
| Neck Type | Square neck for anti-rotation locking |
| Thread Type | Fully or partially threaded shank |
| Standard | DIN 603, ISO 8677, ANSI/ASME B18.5 |
| Common Sizes | M6, M8, M10, M12, M16 |
| Advantage | Explanation |
|---|---|
| Corrosion Resistance | Ideal for outdoor, marine, and humid environments thanks to stainless steel material. |
| Aesthetic Finish | The smooth, round head gives a clean and professional appearance on visible surfaces. |
| High Strength | Stainless steel bolts provide excellent tensile and shear strength. |
| Easy Assembly | The square neck prevents spinning while tightening the nut. |
| Versatile Use | Works perfectly in wood, metal, and composite structures. |
| Type | Description | Applications |
|---|---|---|
| Stainless Steel Carriage Bolt | Corrosion-resistant, durable, and aesthetic | Outdoor furniture, decks, solar mounting |
| Zinc-Plated Carriage Bolt | Affordable, moderate corrosion resistance | Indoor woodworking, machinery |
| Galvanized Carriage Bolt | Heavy-duty corrosion protection | Construction, steel structures |
| Carbon Steel Carriage Bolt | High tensile strength, cost-effective | Automotive, heavy machinery |
Stainless steel carriage bolts are widely used in timber structures, wooden decks, and fences. Their round head bolt design prevents loosening and ensures a secure, smooth surface without sharp edges.
In solar structure systems, stainless steel bolts are used to secure solar rails, brackets, and mounting frames. The A2-70 and A4-80 carriage bolts resist corrosion under sun, rain, and wind exposure.
Carriage bolts are ideal for assembling outdoor benches, tables, and playground equipment, providing both strength and an appealing appearance.
Used in trailers, vehicles, and machinery, the stainless steel carriage bolt fastener delivers excellent performance under vibration and heavy load.
When selecting a carriage bolt, consider the following factors:
Material: Use A2-70 stainless steel bolts for general outdoor use; choose A4-80 for marine or coastal areas.
Size and Thread: Ensure the bolt fits your pre-drilled holes and matches the nut thread type.
Head Style: Round head for visible installations; low-profile head for hidden joints.
Finish: For maximum corrosion protection, select passivated or electropolished finishes.
| Bolt Type | Head Shape | Locking Feature | Typical Use |
|---|---|---|---|
| Carriage Bolt | Round head, square neck | Prevents rotation in wood | Furniture, construction |
| Hex Bolt | Hexagonal head | Requires wrench tightening | Machinery, steel structures |
| Flange Bolt | Hex head with built-in washer | Distributes pressure evenly | Automotive, heavy equipment |
The stainless steel bolt family — including carriage bolts, hex bolts, and flange bolts — offers unmatched corrosion resistance.
In outdoor solar mounting, marine construction, or garden structures, these bolts ensure long-lasting strength without rust or staining.
Using stainless steel fasteners reduces maintenance costs and improves overall structural safety.
The stainless steel carriage bolt is a reliable and durable fastener solution for construction, solar mounting, and machinery applications.
With its round head and square neck design, it provides both functionality and a clean aesthetic.
Whether you’re building furniture, installing solar systems, or assembling heavy equipment, choosing the right stainless steel bolt ensures performance, safety, and longevity.
1. What is the purpose of the square neck on a carriage bolt?
The square neck locks into the material (usually wood or metal) to prevent the bolt from rotating while tightening.
2. Are stainless steel carriage bolts rust-proof?
They are highly resistant to rust and corrosion, especially in A2 or A4 grades, making them ideal for outdoor applications.
3. What sizes of carriage bolts are most common?
Common sizes include M6, M8, M10, and M12, depending on the structure’s load and thickness.
4. Can carriage bolts be used with metal?
Yes, they can be used in metal-to-wood or metal-to-metal joints when paired with the correct washers and nuts.
5. What’s the difference between A2-70 and A4-80 stainless steel bolts?
A2-70 bolts are suitable for general environments, while A4-80 bolts are designed for marine or highly corrosive conditions.
