Hex bolt is a type of fastener commonly used to join two or more objects together. It is characterized by its hexagonal-shaped head and threaded shaft. Hex bolts are also referred to as hexagon bolts, hex cap screws, or machine bolts. The threaded shaft of a hex bolt extends from the head and is used to engage with a nut or threaded hole in the object being fastened. The threads on the shaft can be either coarse or fine, depending on the bolt's diameter and intended use. Hex bolts are available in various materials, including carbon steel, stainless steel, and alloy steel. Different grades and strengths of bolts are designated by markings on the head, such as the ASTM (American Society for Testing and Materials) grade identification.