Comprehensive Guide to Carriage Bolts Everything You Should Know

A carriage bolt is a distinctive bolt which comes with a mushroom head and a circular shank cross-section. The portion immediately below the mushroom head, however, is formed into a square section. The head is usually shallow and dome-shaped. The squared section has a plain unthreaded shank and is of the same size as the bolt shank’s diameter.

What are they used for?

Carriage bolts serve as versatile fasteners, capable of securely joining wood with wood, wood with metal, and even metal with metal. The distinctive shape of these bolts enables them to be self-locking when inserted through a square hole, providing excellent stability, particularly when used with metal components. Furthermore, their adaptability allows them to be effortlessly placed through a round hole in various types of wood, making them an essential and versatile accessory for various applications.

Where do carriage bolts get their name from?

Carriage bolts boast a rich history that spans centuries. Their popularity surged in the early 1800s due to their widespread usage in constructing carriages and carriage wheels, earning them the name "carriage bolts." Over the years, these durable and reliable fasteners have continued to be a staple in various applications, serving as a testament to their enduring design and usefulness.

What are the modern applications of carriage bolts?

In contemporary times, carriage bolts find their most prevalent applications in carpentry and wood construction. They are widely favored by homeowners and professional carpenters alike, playing a crucial role in DIY projects, home maintenance, and repairs. Their ease of use, reliability, and versatility make them an essential component in the construction and assembly of wooden structures, ensuring secure and durable connections for various woodworking tasks. Whether it's building furniture, decking, fences, or other wooden structures, carriage bolts are trusted for their ability to provide robust and long-lasting joints.

What are the different types of carriage bolts?

Carriage bolts come in various types, each tailored for specific applications and featuring distinct physical properties. The most commonly used types include:

Roundhead and Rib-Necked Bolts: These carriage bolts feature a round head and a ribbed neck beneath it. The ribbed neck design enhances their grip in materials, making them ideal for use in soft metals, plastics, and sheet metal.

Roundhead and Short-Necked Bolts: With a round head and a shorter neck, these bolts are suitable for applications where a slightly shallower fastening is required. They are commonly used in wood and thin plywood.

Flathead and Square-Necked Bolts: These carriage bolts have a flat head and a square neck, providing a flush finish when countersunk. Their square neck prevents rotation during installation, making them suitable for wood and other materials where a flush surface is desired.

Fin Necked Bolts: Featuring a neck with fins or ridges, these bolts are designed for use in metal applications, providing added stability and grip in thin materials.

Carriage bolts, in all these types, are highly versatile and can be utilized in various materials, such as soft metals, plastics, wood, sheet metal, and thin plywood. Their adaptability makes them indispensable for a wide range of projects across different industries, ensuring secure and reliable connections in diverse applications.

Why use carriage bolts?

How much weight can a carriage bolt hold?