Bolts hold materials together by providing pressure to the bolt's head, which tightens the nut. To make bolted joints, they go together with tapped holes and nuts. They're easy to tighten using wrenches or pliers because they're externally threaded. Bolts can be used in a variety of ways based on their shape, head type, and size. Hex head, U-bolts, eye bolts, carriage, elevator, plow, and flange are the most frequent types of bolts.