What is an Eye Bolt?

An eye bolt is a special type of fastener that features a lollipop-like shape. One end of the eye bolt resembles the threaded end of a screw, while the other side is forged into a circular shape. In a standard unit, the shank of the bolt is centered below the mid-point of the circle. Specialty eye bolts may also be offset, or cranked, so that the shank sits off to one side of the circle.

Typically, and eye bolt is used to secure a cable, string, wire, or chain to some other object. For example, these bolts may be inserted into a ceiling or beam to support ductwork and plumbing pipes. They may also hang a boxing bag or flower pot from a ceiling or porch. An eye bolt installed in the floor can help support a hanging object and increase stability. They units may also be installed in a wall to hang wires or strings to support a painting.

Depending on the function and quality, eye bolts either feature a forged or welded construction. In a forged bolt, the eye at the top is made by bending a piece of steel to form a loop that doesn't quite close completely. Welded bolts feature a fully-closed circular eye welded to a base or shank. Both can be used in a variety of applications, but welded bolts tend to be required for the most extreme installations.

The different types of threads on an eye bolt can help users distinguish between those designed for wood and those made to work with metal. Eye lags, or eye bolts designed for wood, feature very course threads along the shank as well as a pointed tip to bite into the wood. Sheet metal lags, or machine eye bolts, feature fine threads spaced very close together to provide a strong hold in metal objects. Both wood and metal bolts may feature a full or partially-threaded shank depending on the application.

When choosing an eye bolt, installers must find a unit that can safely support the required load. Generally, longer bolts and those with a thicker shank can support heavier weights. A large diameter eye can accommodate thicker objects like chains or heavy cables, while eyes with a smaller diameter can accommodate strings and thin wires.

Many eye bolts are made of carbon steel, but like all steel objects, these bolts may rust or corrode over time. Bolts used outdoors should be made from galvanized steel to resist rust from rain and other forms of precipitation. If the eye bolt will be used around chemicals or in an industrial setting, stainless steel eye bolts will minimize the risk of corrosion and help the bolt hold up more effectively over time.