Drawing Office Practice in Relation to Interchangeable Components

The paper describes some features of the work of a special Service Committee set up by the Admiralty, for the purpose of standardizing drawing office practice in certain of their design departments.

Basic principles are established for the guidance of designers and draughtsmen when preparing drawings for interchangeable components, and logical methods of approaching solutions to dimensional problems and of stating these on drawings are discussed. Particular attention has been paid to such problems as the best method of analysing, and dimensioning and applying tolerances to interchangeable components which involve tapered, concentric, or positional features such as holes and studs.

Stress is laid upon the need for foreseeing, and avoiding as far as possible in the design stage, any special difficulties which may arise in practice in the construction of manufacturing equipment or of practical gauges for controlling the dimensions of components.

It is understood that the British Standards Institution have in contemplation the preparation of a handbook dealing with the subject of the dimensioning of production drawings and of indicating the tolerances on them. Such a handbook, when completed, not only would be of great use to industry at large, but wouldal so form a valuable textbook for courses of instruction to engineering students in technical colleges and universities. It is hoped that this paper may be the means of stimulating thought on this aspect of interchangeable manufacture and that it will provoke discussion which may lead to the development of a uniform system suitable for use both by Service Departments and by industry in general.