An eye screw, also referred to as a screw eye or an eye bolt, is a special type of screw that is curved into a loop on one end instead of being flat. A traditional screw has a flat end with an indent for the screwdriver to be inserted into, and the other end is made up of the threads of the screw, the rotating spiral-like lines that curve around the screw and allow it to go into materials more easily. The eye screw has threads at one end, but not on the top. Instead, a large circle is formed by the bent end of the screw.
The advantage of an eye screw is that it allows the user to hang things from it and takes little time to install. It may be used to attach two materials together or simply to hang a picture on a wall. They are also used to hook cables together for supporting objects. The eye screw can only hold a certain amount of weight, however, and is best for holding light to medium-weight objects. For this reason it is not the best choice to use in heavy construction.
When the user simply wants to hang an item on a wall, she can push the point of the screw into the wall and rotate it by holding on to the circular end. If the wall or wood is soft enough, the screw will go in. If not, a wrench or other tool may be required. Once the thread has been screwed into the wall, a wire or a hook is placed through the circular end to support the item. If the eye screw is removed, a small hole will be left behind unless the owner has it filled in.
Stainless steel and brass are the most common materials used in creating the eye screws. A matching screw may also be purchased that has a hook on the end instead of a full circle. This allows the hooked screw to be inserted into the eye screw for attaching items together. Depending on the type of screw, they can be used in machinery if the pressure on them will not be too great. These eye screws need a shoulder and typically a collar attached to them, and can usually support angular loads up to 45 degrees, though this can vary with the type and size of screw.