The Practical Application of the New British Standard System of Limits and Fits

This paper suggests methods by which the new British Standard system for limits and fits can be most efficiently applied in industry, and proposes a method of approach by which series of fits for various purposes can be selected from those shown in the British Standard. It refers particularly to Part II of the Standard which gives data on the application of various types of fit.The choice of tolerances is discussed in relation to machine capabilities and fit requirements, and a series of fits for general engineering requirements is proposed. Methods of assisting the correct application of tolerances and fits in the design stage of a piece of equipment are suggested, and the use of methods of selective assembly is shown to be practicable, using standard limits. Assembly fits for ball and roller bearings are discussed, and it is suggested that a standard series of such assembly fits should be established.