Carriage Bolts: A headed and externally threaded mechanical devices designed for insertion through holes in a soft material such as a wood or pre-punched hole in harder material in which the square shank below the head grooves into to prevent the bolt from spinning during installation and tightening of a nut. All of our carriage bolts come with our 100% satisfaction guarantee. Zinc plated low carbon carraige bolts are the most common carraige bolt sold today. Please select the type of carraige bolt your looking for below.