An eye bolt is a screw

Screw

A screw, or bolt, is a type of fastener characterized by a helical ridge, known as an external thread or just thread, wrapped around a cylinder. Some screw threads are designed to mate with a complementary thread, known as an internal thread, often in the form of a nut or an object that has the...

 with a loop on one end and threads

Screw thread

A screw thread, often shortened to thread, is a helical structure used to convert between rotational and linear movement or force. A screw thread is a ridge wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread...

 on the other end. Eye bolts are commonly used to attach cables to objects, for instance attaching a string

Rope

A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...

 to the back of a painting

Painting

Painting is the practice of applying paint, pigment, color or other medium to a surface . The application of the medium is commonly applied to the base with a brush but other objects can be used. In art, the term painting describes both the act and the result of the action. However, painting is...

to allow the painting to hang from a nail on a wall.

Machine screw threading

Machinery eye bolts are fully threaded and may have a collar, making them suitable for use with angular loads up to 45°. Eye bolts without a shoulder should not be used for angular loads.

Wood screw threading

Wire eye lags (also called screw thread eye bolts, eye screws, or turned/bent eye lags) have a wood screw thread for use in wood or lag anchors. Like wire eye bolts, wire eye lags are intended for light duty applications and should not be used for angular loads.

Forged vs. bent eye construction

Eye bolts made by bending a rod or wire into a loop are only suitable for light duty applications, as heavy loads can cause the eye to open. For high loads, eye bolts with forged or welded loops should be chosen, as they can withstand loads up to the tensile strength of the material of which they are made.