Engineering drawings are the graphical representations of ideas. Graphical representations are recognized as an efficient and nearly universal means of communicating designs, instructions, and plans. These documents graphically describe shapes, sizes, and materials used in a product. Drawings are the primary method used to control production. Standard practices are used in engineering drawings to avoid confusion and improve the effectiveness of communication. This chapter provides an overview of some of the recommended practices and standards used in the graphical language of engineering drawings. There are two systems of projection recognized internationally for multi-view drawings. Dimensions describe the details of a part so it can be constructed to the proper size. The three most common types of fits are clearance, interference, and transition. The most common requirement of a tolerance on a dimension calls for parts to be 100% interchangeable. Surface texture specifications are critical to assuring the proper function of parts such as bearings or dies.
By Gary Conner
By George N Bullen FSME