Hexagon bolts, also called hex head bolts, are threaded machine bolts used with nuts or in threaded holes. As the name suggests, hexagonal head bolts are hexagonal heads (6 sides) made from grade 2 galvanized steel, 316/304 stainless steel and grade 5 galvanized steel.
Hex head bolts are designed to secure objects within or against other objects for a secure hold that won't loosen. Applications for hex bolts include fastening steel to steel, wood to wood, and other materials found in the construction of projects such as highway structures, bridges, and buildings.
Hex bolts have more torque than traditional round screws and tend to rotate when the bolt is tightened and loosened, requiring a wrench or socket to secure it. Hex bolts are usually installed and removed using a socket wrench.
Hex head bolts are available in fully threaded and partially threaded styles. When mated to fully threaded holes, use fully threaded hex head bolts. Partially threaded bolts are more rigid and have an unthreaded area under their heads to provide greater holding strength when force is applied to the structure they are fastened to.
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Hexagon head bolts are not hexagon head screws
It's common to mistake hex head screws for hex bolts, but the two fasteners differ in many ways, including how they are used and installed.Install the hex bolt by turning the nut to tighten the fastener.
Hex head screws are assembled and tightened by rotating the head into a threaded hole.Hex bolts have neither a washer surface nor a chamfer point.
Hex head screws have washer surfaces on the bearing surface and chamfer points.Hexagon bolts are commonly used in the construction industry where mechanical properties are more important than dimensional tolerances.
Hex head screws are often used in precision applications that require tight tolerances.
Hex Head Bolt Head and Thread Dimensions
Information on technical dimensions of heads and threads of hexagonal head screws of all grades and materials. Technical dimensions include body diameter, flat width, corner width, head height and thread length.
Standard thread length for hex head bolts:
Bolt length ≤ 6 inches: Thread length = (2 X diameter) + 1/4 inch
Bolt length > 6 inches: Thread length = (2 X diameter) + 1/2 inch
NOTE: Most stock hex bolts 10" and longer will have 6" threads.
Basic specifications of hexagon head bolts:
Diameter: 1/2 – 1 inch
Grade: ASTM A307 Grade A, F1554 Grade 36
Length: up to 30 inches
Surface treatment: ordinary galvanizing and hot-dip galvanizing