Carriage Bolts in Bolts

Carriage bolts have a distinctive rounded head with a smooth, domed top and a square section underneath the head. This square neck fits into a square hole or grips the wood to prevent the bolt from turning when tightening the nut. In contrast, regular bolts usually have hexagonal heads designed to be turned with a wrench. Carriage bolts are often used in wood applications where a smooth, finished look is desired on the bolt head side, and they provide a secure fastening without the need for a wrench on the head.

Carriage bolts are ideal when you need a smooth, rounded head on one side of the fastener and a secure hold without the bolt spinning during installation. They work well for wood-to-wood or wood-to-metal connections where appearance matters, such as furniture or fencing. Lag bolts, on the other hand, are threaded fasteners that screw directly into wood and are better for heavy-duty applications requiring strong holding power without a nut. Choosing carriage bolts is beneficial when you want a clean look and the ability to tighten from the nut side.

Choosing the right size carriage bolt depends on the thickness of the materials you're fastening and the load requirements.

• Length: The bolt should be long enough to pass through all materials plus enough length to attach a nut securely.
• Diameter: Select a diameter that fits snugly in the pre-drilled hole to prevent movement.
• Thread pitch: Match the bolt's thread size with compatible nuts or washers.

While carriage bolts can be used without washers, adding washers is often recommended to protect the material and improve fastening.

• Washers distribute the pressure from the nut evenly, preventing damage to softer materials like wood.
• They also help reduce loosening from vibration by providing a smooth surface for the nut to tighten against.
• In some cases, washers can prevent the nut from digging into the material, extending the life of the joint.

Carriage bolts are commonly used in a variety of home improvement projects where a smooth, finished bolt head is preferred. Typical uses include:

• Building wooden fences and gates, where the rounded head provides a clean look and prevents snagging.
• Assembling outdoor furniture, offering secure fastening without exposed sharp edges.
• Attaching metal hardware to wood, such as brackets or hinges.
• Constructing decks or playground equipment where safety and appearance are important.