Primarily used for aesthetics in new buildings or in the railroad industry, square head bolts are externally threaded fasteners, generally made from low or medium carbon steel. They have square-shaped external wrenching heads, which offer a large bearing area for positive gripping. Our selection of Grade A square head bolts come in A307 Plain, Zinc and HDG as well as a variety of sizes to suit the job at hand. If you don’t see the item you need, send our knowledgeable staff an email or contact us at 866-463-2910. Shop Online Below!