Basic Engineering Standards and Their Place in Design

In this paper standardization in design is considered. The argument is developed tat the detailed design of the parts of a mechanism demands a logical approach. The designer should state on the drawing, in the simplest possible terms, what he really wants. The necessary range of basic (or abstract) engineering standards, both for him to achieve this aim and to provide for economic production, are given.

The basic standards cover definitions, geometric analysis, ultimate standards of size, basic sizes, limits and fits, measurement, surface texture, drawing practice, standard forms (for example, screw threads), and standards of design. Their nature and scope are examined in general terms and some of the main compromises necessary are discussed.

The necessity is shown for a sound framework, wide enough to cover the normal needs of all engineers. The dangers of a parochial outlook are stressed and the needs of both small and large producers are emphasized. These standards are shown to be the essential preliminary to sound standardization of articles, which should be a natural by-product of sound design. Their main economic value, however, is that they affect every article which the engineer designs.

At the present time there is only a partial framework and much disagreement on details. To standardize articles before agreement has been reached on the approach to detailed design of the articles, leads to difficulties in standardization and sometimes to bad standards. Several good solutions can be propounded for most problems, and many different ones are in local use. A single, wide, and all-embracing plan which can be used by everyone is needed. Education and explanation can then lead to general use, to the lasting advantage of the engineering industry.