Carriage Bolt

A carriage bolt is a component used in fabricated metal product manufacturing. It features a rounded head and a square neck that resists rotation when installed in a prepared hole. This design allows the bolt to be tightened from the nut side without requiring a tool on the head, making it suitable for applications where a smooth, exposed head is desired. Common uses include timber connections, gates, shelving, and metal-to-wood joints. The bolt is typically installed by inserting the square neck into a matching hole, which prevents the bolt from turning as the nut is tightened. Buyers should specify the head series, square-neck geometry, thread, length, material, property class, and finish. The standards listed here, such as DIN 603, govern particular forms and do not make sizes, materials, or finishes interchangeable across different standards. The request for quotation (RFQ) should state the exact standard or drawing, required configuration, quantity, and inspection evidence. Materials on file include carbon steel and stainless steel. Parameters such as nominal size, material, strength, and surface finish must be confirmed against the selected standard and supplier evidence. This directory entry serves as a neutral reference; it does not imply certification or compliance of any specific product. Always verify model-specific values and standards with the legal manufacturer or supplier before procurement.

The carriage bolt operates by inserting its square neck into a matching hole in the workpiece. The square shape of the neck bears against the sides of the hole, preventing the bolt from rotating when torque is applied to the nut on the opposite side. As the nut is tightened, the bolt is pulled through the hole, creating a clamping force between the head and the nut. The rounded head provides a smooth exterior surface, reducing snagging and improving appearance. The square neck ensures that the bolt remains stationary during tightening, eliminating the need for a wrench on the head side. This principle is effective in applications where access to the head is limited or where a flush, smooth finish is required. The clamping load is generated by the tension in the bolt, which is transferred to the connected parts. Proper hole preparation is critical to ensure the square neck engages correctly and the bolt performs as intended.