Carriage Bolt
Round head with square neck design, suitable for wood and structural connections.

Product Introduction
A carriage bolt is a special bolt with a round, smooth head and a square neck, also known as a round head square neck bolt or coach bolt. During installation, the square neck embeds into the connecting material, preventing the bolt from rotating when the nut is tightened, ensuring a secure fastening.
WT Fasteners professionally produces various specifications of carriage bolts, including standard carriage bolts, large round head carriage bolts, high-strength carriage bolts, and stainless steel carriage bolts. We can provide different materials, grades, lengths, and surface treatment options based on customer requirements.
Carriage bolts are widely used in wooden structures, furniture manufacturing, construction engineering, steel structures, mechanical equipment, and outdoor facility connections.
Product Features
1. Anti-Rotation Structural Design
The square neck below the round head can embed into the material, effectively preventing the bolt from rotating during installation.
2. Safe and Aesthetic
The round, smooth head reduces exposed sharp edges, improving safety and providing a cleaner appearance.
3. Easy Installation
No additional tools are needed to hold the bolt head; installation can be completed quickly with a nut.
4. High-Strength Materials
Made from high-quality carbon steel, alloy steel, and stainless steel, offering excellent load-bearing capacity and durability.
5. Customization Support
Custom head shapes, square neck sizes, lengths, and surface treatments can be tailored based on customer drawings or samples.
Product Parameters
Product Name:
Carriage Bolt
English Name:
Carriage Bolt / Coach Bolt
Common Standards:
- DIN 603
- ISO 8677
- GB/T 12
- ANSI Standards
Materials:
- C1022 Carbon Steel
- Low Carbon Steel
- Alloy Steel
- Stainless Steel 304
- Stainless Steel 316
Strength Grades:
- Grade 4.8
- Grade 8.8
- Grade 10.9
Size Range:
M4-M24
(Custom sizes supported)
Length:
10mm-300mm
Thread Types:
- Full Thread
- Partial Thread
Surface Treatments:
- White Zinc
- Yellow Zinc
- Black Zinc
- Hot-Dip Galvanized
- Dacromet
- Black Oxide
- Stainless Steel Natural Finish
Product Types
DIN603 Carriage Bolt
The most common standard type, with a round head and square neck, widely used in furniture and construction connections.
Large Round Head Carriage Bolt
Features a larger head diameter, suitable for connections requiring greater bearing area.
High-Strength Carriage Bolt
Manufactured from high-grade materials, suitable for structures bearing significant loads.
Stainless Steel Carriage Bolt
Excellent corrosion resistance, suitable for outdoor and humid environments.
Short Square Neck Carriage Bolt
Ideal for thin plates, furniture, and special installation scenarios.
Application Areas
Carriage bolts are widely used in:
- Wooden structure construction
- Furniture manufacturing
- Outdoor wooden products
- Steel structure engineering
- Bridges and guardrails
- Mechanical equipment
- Agricultural equipment
- Solar mounting systems
Packaging Methods
Available based on customer requirements:
- Plastic bag packaging
- Small box packaging
- Carton packaging
- Woven bag packaging
- Pallet packaging
- Customer-branded packaging










































