Types of Bolts

Types of Bolts

There are many types of bolts designed for different purposes. In this article, we gonna look into some of the popular ones.

Hex Bolts

Hex bolts, also known as hexagonal-headed bolts, are bolts with a hexagonal head. A hexagonal head is a 6-side polygon. Because of their hexagonal shape, we can wrench them at different angles.

Hex bolt

However, the edges of the head can wear out due to corrosion or extreme torque. In such cases, hex bolts are difficult to wrench.

Square Bolts

As the name suggests, square bolts are bolts that have a square head. Compared to hex bolts, square bolts can handle more torque. But it can only operate in 90-degree angles, so square bolts are efficient compared to hex bolts.

Pentagon Bolts

Pentagon blots are a type of bolts with pentagon shape heads. And it has the same advantages as hexagonal nuts. Moreover, it’s commonly used for high torque applications.

Carriage bolts

Carriage bolts, also known as domed head bolts, coach bolts, mushroom head, and round head bolts, are designed with a round-shaped head with no threads. Because of its shape, it’s difficult to wrench. Therefore, we usually use a hammer to install the carriage bolts and use nuts to fix them in place.

Carriage bolts are used when the surface finish is important or to discourage repairing. If you want to remove a carriage bolt, you need to lose the nut and hammer from the opposite side of the head.


U bolts are designed in the letter U shape to hold something. And we commonly see these U bolts in suspension systems of automobiles to hold the lead springs on the differential. And it’s also used in pipelines to hold pipes.

Lag Bolts

Lag bolts are designed to screw into the material and do not require nuts for fastening. It can be used with wood, metal, concrete, and many materials. Even it’s not possible to screw through hard solid metals, we can drill the solid and attach any other material that can be welded to the metal.