Product Description 50 Pack 1/2-13 X 1-1/2" Hex Bolt, Low Carbon Steel, Coarse Thread. . From the Manufacturer Hex Bolts are bolts with hexagonal heads and machine threads for use with a nut or in a tapped hole. As the most common type of bolt, Hex Bolts are standard hex bolts with a washer face under the head. Usually Hex Bolts are only partially threaded.