When to Use Carriage Bolts Instead of Regular Bolts

Carriage bolts and regular bolts are both widely used in fastening, but they serve different purposes. A carriage bolt has a smooth, round head and a square neck underneath, while a regular hex bolt has a hexagonal head that can be gripped with a wrench.

The square neck helps prevent the carriage bolt from turning when the nut is tightened. This makes carriage bolts a practical choice for wood connections, furniture, and outdoor structures where a smooth head is preferred.

Carriage Bolts

Carriage Bolts for Wood Applications

Carriage bolts are commonly used to join wooden components. When installed in a properly sized hole, the square neck grips the wood and helps keep the bolt from spinning as the nut is tightened from the opposite side.

Typical applications include:

• Wooden tables, chairs, and benches
• Decks and fences
• Garden structures and sheds
• Timber frames and outdoor furniture

Another advantage is the rounded head. Unlike a hex bolt, it has no exposed corners, giving visible wood connections a cleaner finish. This is one reason carriage bolts are often used in furniture and woodworking projects.

Carriage Bolts

When Carriage Bolts Are a Better Choice

Carriage bolts are particularly useful when the bolt head needs to remain smooth and unobtrusive. They can also make installation easier when there is limited access to the head, provided the square neck can grip the material properly.

However, the square neck does not prevent rotation in every situation. If the hole is too large, or the material is too hard for the neck to bite into, the bolt may still spin during tightening. The hole size and installation method therefore matter.

For outdoor projects, it is also important to consider corrosion resistance. The choice between zinc-plated carbon steel and stainless steel, for example, depends on exposure to moisture and the conditions in which the fastener will be used.

Carriage Bolts

Carriage Bolts vs Regular Hex Bolts

The main difference comes down to head design and installation requirements.

Carriage bolts are often preferred for wood connections where a rounded head and resistance to turning are useful. Regular hex bolts are more suitable for many metal assemblies and mechanical applications where the bolt head needs to be held or tightened with a wrench.

Neither type is automatically stronger than the other. Strength depends on factors such as material, bolt grade, dimensions, and the design of the joint. For load-bearing applications, these factors should be checked before selecting a fastener.

Carriage Bolts from Xinchi Fastener Factory

Established in 2007, Xinchi Fastener Factory operates 102 cold heading machines and has a daily production capacity of over 10 million pieces. Our new factory covers 30,000 square meters and consists of two six-story buildings.

Xinchi Fastener Factory

We supply carriage bolts and a range of other fasteners, including DIN1624 T nuts, thread insert nuts, rivet nuts, Hopper Feed T nuts, flange bolts, DIN 571 wood screws, bolts, and washers. Our products serve furniture, woodworking, and other industrial applications. Contact Xinchi Fastener Factory for product specifications and custom requirements.