Carriage Bolts

A carriage bolt, also known as a coach bolt or a round-head square-neck bolt, is a versatile fastener primarily used to secure metal to metal or metal to wood. It stands apart from other bolts due to its distinctive shallow mushroom head and the square cross-section of its shank immediately beneath the head. This square neck allows the bolt to lock securely in place when inserted through a square hole in a metal strap, enabling installation with just one tool—a spanner or wrench—from one side. The shallow dome-shaped head of the carriage bolt adds to its unique design, while the shank remains unthreaded and its diameter matches the side of the square cross-section.

The carriage bolt was invented for use in conjunction with iron strengthening plates on both sides of a wooden beam, with the square portion of the bolt fitting snugly into a square hole in the ironwork. It is commonly used to fasten bare timber, as the square section provides sufficient grip to prevent rotation.

Carriage bolts are extensively utilized in security fixings, such as locks and hinges, where the bolt must be removable from one side only. The smooth, domed head and the square nut beneath prevent unauthorized unlocking from the insecure side, enhancing security.

Advantages and Services

We welcome customized special hardware and sizes to meet your specific needs. Our team provides technical service and consultation to ensure you get the right carriage bolt for your application. With advanced production equipment and technology, we offer competitive factory-direct prices along with professional service. Strict quality inspection is conducted on both materials and finished products to ensure the highest standards. We focus on every detail throughout the service, production, packing, and shipment processes.

Application

Wood Applications of Carriage Bolts
Carriage bolts are safe and reliable fasteners ideal for securing two planks together in various applications. Commonly found in home construction, pilings, ready-to-assemble furniture, fences, patios, and outdoor decks, carriage bolts are also a preferred choice due to their aesthetic appeal. They add a 'finished' look to any surface, making them the number one choice for applications where smoothness is desired.

Metal Applications of Carriage Bolts
While carriage bolts are particularly suited for wood applications due to their unique advantages, they can also be used in place of regular bolts in metal applications. To ensure a tight fit between two metal components, it is crucial to ensure that the hole for the fastener matches the size of the square shank. Although the process may be more tedious, carriage bolts can be used in metal applications by regularly removing the drill to test and check progress. For improved fastening in metal applications, it is advisable to add a washer and nut on the other side of the bolt.

Throughout its applications, the carriage bolt remains a reliable and versatile fastener, providing strength and security while enhancing the aesthetic appeal of any project.