A square neck bolt, also known as a carriage bolt or coach bolt, is a type of threaded fastener that features a square-shaped portion just beneath the head of the bolt. This square neck, or carriage, prevents the bolt from turning when it’s tightened or loosened, making it especially useful in applications where one side of the connection should remain stationary while the other side is being tightened.
Here are the key characteristics of a square neck bolt:
Head: The head of a square neck bolt is typically round or domed, and it may have various drive types, such as slotted, Phillips, or hex.
Square Neck: The square neck is a portion of the bolt, just below the head, with a square cross-section. This square neck prevents the bolt from spinning within the hole or slot it’s inserted into.
Threaded Shaft: The rest of the bolt features a threaded shaft, which allows it to be inserted into a pre-drilled hole or slot and tightened with a nut on the opposite side.
Applications: Carriage bolts are commonly used in wood-to-wood or metal-to-wood connections. They are frequently used in construction, woodworking, and furniture assembly. The square neck prevents the bolt from turning, allowing for a more secure and stable connection.
To install a square neck bolt, you typically insert it through a pre-drilled hole or slot in one of the materials you’re connecting. Then, you secure it by placing a nut on the threaded end of the bolt and tightening it. As you tighten the nut, the square neck prevents the bolt from spinning, ensuring a secure and stable connection.
Other names: round head square neck bolt, carriage bolt, coach bolt
Square neck bolts, offer several advantages in various applications due to their unique design and features. Here are some of the advantages of using square neck bolts:
Resistance to Rotation: The square neck under the head of the bolt prevents it from rotating within the hole or slot. This feature ensures that the connected materials remain in the desired position, making square neck bolts suitable for applications where a non-rotating joint is essential.
Secure Fastening: Square neck bolts provide a secure and stable connection, making them suitable for applications where vibration or movement might otherwise cause conventional bolts to loosen.
Ease of Installation: Installing square neck bolts is relatively straightforward. The square neck holds the bolt in place during installation, allowing for easy tightening of the nut.
Wide Range of Materials: Square neck bolts are available in various materials, including steel, stainless steel, and brass. This versatility in material options allows you to choose a bolt that is compatible with the specific requirements of your application, such as corrosion resistance.
Versatile Applications: Square neck bolts are commonly used in woodworking, construction, and furniture assembly. They are also suitable for applications where a clean and finished appearance is desired, as the bolt head sits flush with the material surface.
Tight Sealing: In some applications, square neck bolts can be used to create a tight seal or clamp, especially when combined with washers or other fasteners.
Tamper Resistance: When installed with the square neck on the outside of an assembly, square neck bolts can provide some level of tamper resistance since the square neck makes it challenging to remove the bolt without access to both sides of the connection.
It’s important to choose the right size, material, and head type of square neck bolt for your specific application to maximize the benefits and ensure a secure and reliable connection.