The Library Shelf

Reviewing this Standard from the viewpoint of the aircraft engineer, one is immediately conscious of the fact that much of the subject matter does not come within his province. A discreet silence is therefore observed on the notes concerning qualitative tolerances on machined parts. This is, however, only one of a comprehensive range of subjects which have been gathered together under the heading of ‘Dimensioning and Tolerancing’. Any attempt, such as this, to standardize the method of dimensioning an engineering drawing, merits the serious attention of the designer and the production engineer. At the moment, much time, money and raw material is wasted because of the failure of the designer and the manufacturer to understand one another completely, through the medium of the blueprint. In these days of world trade, and more particularly in time of war, oceans and continents may separate these two ends of the production line. If correspondence or personal visits between them are necessary to straighten out manufacturing problems, the drawing can be said to have failed in its purpose. Intelligent interpretation of this standard, by both parties, will remove many of the present difficulties.