Overview
Carriage bolts are round-head fasteners with a square neck beneath the head designed to prevent rotation during installation. When inserted into wood or square-punched metal holes, the square shoulder locks into place, allowing the nut to be tightened without the bolt turning.
Carriage bolts are widely used in construction, structural framing, agricultural equipment, wood-to-wood connections, fencing, docks, and industrial fabrication.
Offshore Milling & Sourcing supports bulk and factory-direct sourcing programs for carriage bolts, serving distributors, OEM manufacturers, contractors, and steel fabricators requiring dependable volume supply and competitive pricing.
Types of Carriage Bolts Available
- Standard Round Head Carriage Bolts
- Short Neck Carriage Bolts
- Ribbed Neck Carriage Bolts
- Flat Head Carriage Bolts
- Stainless Steel Carriage Bolts
- Structural Carriage Bolts
- Custom Per-Print Carriage Bolts
Specifications
- Diameter Range: 1/4″ – 1″ (Metric sizes available)
- Length Range: 1/2″ – 24″+
- Thread Type: UNC / UNF / Metric
- Neck Type: Square / Ribbed
- Standards: ASTM A307 / SAE J429 / DIN 603 / ISO 8677
Carriage bolts are engineered for wood applications and structural fastening where anti-rotation features are required.
Grades Available
- Grade 2 (Low Carbon Steel)
- Grade 5
- Grade 8
- ASTM A307
- Custom structural grades upon request
Grade selection depends on load requirements and application type.
Materials
- Low Carbon Steel
- Medium Carbon Steel
- Stainless Steel 304
- Stainless Steel 316
- Hot Forged Structural Steel
- Specialty alloys upon request
Material choice is determined by strength requirements and environmental exposure.
Finish & Coating Options
- Zinc Plated
- Yellow Zinc
- Black Oxide
- Hot Dip Galvanized
- Mechanical Galvanized
- Plain Finish
- Stainless (Natural Finish)
- Custom corrosion-resistant coatings available
Hot-dip galvanized carriage bolts are especially common for outdoor construction and agricultural use.
Industries Served
- Structural Steel Fabrication
- Wood Construction
- Fencing & Decking
- Agricultural Equipment
- Highway & DOT Projects
- Marine & Dock Applications
- OEM Manufacturing
- Industrial Distribution
Applications
- Wood-to-wood fastening
- Wood-to-metal connections
- Structural framing
- Fence posts and rails
- Dock construction
- Equipment assembly
- Heavy timber construction
Carriage bolts are commonly specified for projects requiring smooth finished heads and anti-rotation performance.
Strategic Bulk Sourcing Programs
Carriage bolts are one of the most commonly imported fastener categories due to consistent demand in construction and distribution markets.
We support:
- Factory-direct container programs
- Mixed SKU consolidation
- Secondary sourcing strategies
- Blanket purchase agreements
- Custom forging programs
- Private label packaging
Our sourcing programs are structured for distributors and OEMs seeking long-term supply stability and scalable capacity.
Packaging Options
- Bulk cartons
- Palletized shipments
- Gaylord containers
- Custom-labeled packaging
- Retail-ready packaging
- Mixed container programs
Request a Quote
To receive pricing for carriage bolts, please provide:
- Diameter
- Length
- Grade
- Finish
- Quantity
- Delivery timeline
Engineering drawings may be included for custom parts.
