Carriage bolts are one of the most widely recognized round head square neck bolts used throughout industry. Their smooth rounded head provides a finished appearance while the square shoulder beneath the head is drawn into a properly sized hole as the nut is tightened. This prevents the bolt from rotating, allowing installation from one side of the assembly without requiring a wrench on the head.
Originally developed for wooden carriage construction, carriage bolts remain the preferred fastener for wood-to-wood and wood-to-metal assemblies. Today they are widely used in playground equipment, timber structures, recreational products, industrial equipment, material handling systems and countless OEM assemblies where appearance and dependable anti-rotation performance are important.
G-Fast manufactures standard ASME B18.5 carriage bolts together with made-to-print carriage bolts produced directly from customer drawings and specifications. Standard square neck carriage bolts are complemented by short square neck and ribbed neck designs that improve performance in specific applications and materials.
Materials include low carbon steel, alloy steel, stainless steel and bronze together with customer-specified materials. Depending on the application, carriage bolts may be supplied with zinc plating, black oxide, passivation or other specified protective finishes. Metric and inch configurations are available.
Every custom project begins with FASTENEERING®, our engineering review process that evaluates the drawing, material, tolerances and manufacturing method before production begins. Recommendations are made whenever manufacturability or production efficiency can be improved while preserving the customer's engineering intent.
Carriage bolts provide dependable fastening for structural and OEM assemblies where a smooth finished head and anti-rotation square shoulder are required.
- One-sided installation after the square shoulder engages the material.
- Smooth rounded head for a clean finished appearance.
- Standard square neck, short square neck and ribbed neck styles.
- Standard ASME B18.5 and made-to-print production.
- Available in multiple materials, finishes and strength grades.
- OEM production quantities and scheduled blanket releases.
Additional custom configurations are available for specialized industrial applications.
G-Fast manufactures standard and custom carriage bolts directly from customer drawings, CAD files and approved samples. Virtually every feature of the fastener can be modified to meet specific OEM requirements, including head diameter and profile, square neck dimensions, shoulder length, shank diameter, thread length, thread configuration, materials, heat treatment and protective finishes.
In addition to traditional square neck carriage bolts, round head bolts may also be manufactured with a knurled shoulder, a plain cylindrical shoulder or without a shoulder entirely when required by the application. Secondary operations including drilling, machining, thread modifications and special coatings are available.
Every project is reviewed through FASTENEERING® to determine the most efficient manufacturing method while maintaining the customer's engineering intent. Whether the requirement is a standard carriage bolt or a completely custom fastening solution, G-Fast supports prototype development, OEM production quantities and scheduled blanket releases.
