engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more speciali ...

, a boss is a protruding feature on a work piece. A common use for a boss is to locate one object within a pocket or hole of another object. For instance, some

motors An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power g ...

use a precisely machined boss on the front face to locate it on the mating part. Like a process on a bone, bosses on

casting Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a ''casting'', which is ejecte ...

s can provide attachment points or bearing surfaces. The term 'boss' when used in engineering can also relate to a finishing edge around (usually) a circular opening that allows the opening to locate onto, or within another opening thus locating or joining two items together with a view to the location or joining being temporary or semi-permanent. A common everyday example of a boss is the housing of the rotation spindle in a washing machine drum, or on a cylinder lawn mower at the end of the cutting blade cylinder which may house a bearing set to allow the cylinder to rotate through one plane, but held firm in another plane. A boss can also be a brass eyelet on a sail. It is a generic term to describe an item designed to facilitate the use with, within, on or around another item whereby one cannot operate properly without the other. The word 'boss' is also often used to describe the end of a shaft on a boat to which a propeller might attach. A boss may also refer to a mounting feature that will receive a screw or thread-forming screw. In

computer-aided design Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve co ...

applications, a boss is a feature used to describe a type of

extrusion Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex c ...

. The word boss comes from the

Middle French Middle French (french: moyen français) is a historical division of the French language that covers the period from the 14th to the 16th century. It is a period of transition during which: * the French language became clearly distinguished from t ...

word ', which means protuberance.

References

Metalworking terminology {{Mech-engineering-stub

See also

References