Machines of various size and complexity are made up of assem-blies. units and components.The course "e;Design of Machine Elements"e;, as a branch of engineering, outlines the methods, rules and standards for designing elements on the basis of the conditions of their operation in a machine, with a view to giving them the most advantageous forms and sizes, choosing the required materials, the degree of accuracy and surface finish and providing for adequate conditions of manufacture. In doing this, one of the main tasks of the designer should be to ensure that, material is economised wherever nossihle.