Below is a list of Hex Bolts manufacturers from Harleysville, Pennsylvania. Hex bolts are threaded mechanical fasteners that have six sided heads and are often used in conjunction with a hex nut to adjoin two surfaces or objects securely. Also known as hexagon or hexagonal bolts, the name of this device is a derivative of the specific number of sides on the head, or the top portion of the bolt. A combination of nut bolt and screw bolt, the hex is one of the most universally used of all bolts.