Our carriage bolts are of the highest quality available, and made of 655 Silicon Bronze alloy.
Round head, square neck,
Meets ANSI/ASME B18.5 Standard Specifications:
The formula for determining thread length is: Bolts 6 in. and shorter, 2 diameters plus 1/4 in. Bolts over 6 in. 2 diameters plus 1/2 in. If bolts are too short to apply the formula, the thread will be extended as close to head as possible.