A bearing surface is a mechanical engineering

Mechanical engineering

Mechanical engineering is a discipline of engineering that applies the principles of physics and materials science for analysis, design, manufacturing, and maintenance of mechanical systems. It is the branch of engineering that involves the production and usage of heat and mechanical power for the...

 term that refers to the area

Area

Area is a quantity that expresses the extent of a two-dimensional surface or shape in the plane. Area can be understood as the amount of material with a given thickness that would be necessary to fashion a model of the shape, or the amount of paint necessary to cover the surface with a single coat...

 of contact between two objects. It usually is used in reference to bolted joints and bearings

Bearing (mechanical)

A bearing is a device to allow constrained relative motion between two or more parts, typically rotation or linear movement. Bearings may be classified broadly according to the motions they allow and according to their principle of operation as well as by the directions of applied loads they can...

, but can be applied to a wide variety of engineering applications.

On 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...

 the bearing area loosely refers to the underside of the head. Strictly speaking, the bearing area refers to the area of the screw head that directly bears on the part being fastened.

For a cylindrical bearing it is the projected area

Projected area

Projected area is two-dimensional area measurement of a three-dimensional object by projecting its shape on to an arbitrary plane. This is often used in mechanical engineering related fields, specifically hardness testing, axial stress and terminal velocity....

 perpendicular to the applied force.

On a spring

Spring (device)

A spring is an elastic object used to store mechanical energy. Springs are usually made out of spring steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication...

 the bearing area refers to the amount of area on the top or bottom surface of the spring in contact with the constraining part.

The ways of machine tool

Machine tool

A machine tool is a machine, typically powered other than by human muscle , used to make manufactured parts in various ways that include cutting or certain other kinds of deformation...

s, such as dovetail slides, box ways, prismatic ways, and other types of machine slide are also bearing surfaces.