DigiCat Publishing presents to you this special edition of "An Introduction to Machine Drawing and Design" by David Allan Low. DigiCat Publishing considers every written word to be a legacy of humankind. Every DigiCat book has been carefully reproduced for republishing in a new modern format. The books are available in print, as well as ebooks. DigiCat hopes you will treat this work with the acknowledgment and passion it deserves as a classic of world literature.

AutoCAD is one of the most powerful and economical software for drafting and designing available in the market today. Keeping this software as the platform, Machine Drawing with AutoCAD provides a comprehensive and practical overview of machine dra.

TO THE GERMAN EDITION This book is addressed to those engineering students who are prepared to work-not to such as are content to refurbish existing designs without taking the trouble to understand the trains of thought and the considerations which are needed in true design work. It is a well-established fact that the beginner, confronted by the simplest of design problems, and lacking a pattern or model to suggest a solution, loses his way in endless trial and error unless given positive guidance. In this book, therefore, the author has drawn on his long teaching experience in an attempt to present in a readily understandable and systematic manner a methodical work plan which will enable the beginner practising design problems to reach his objective by a rational route. This approach has the further advantage. con firmed by experience, that in adopting it the student will find his interest and pleasure in design work growing, and his self-confidence increasing. Written with the requirements of general mechanical engineering in mind, the book does not deal with the manufacturing methods typical of light precision engineering. To prevent the book from taking on a size which would have detracted from its clear layout and obscured the main principles presented, the numerical tables, graphs, etc. available for reference in pocket books and textbooks have been omitted.

Chapter 1 BLUEPRINTS When you have read and understood this chapter, you should be able to answer the following learning objectives: Describe blueprints and how they are produced. Identify the information contained in blueprints. Explain the proper filing of blueprints. Blueprints (prints) are copies of mechanical or other types of technical drawings. The term blueprint reading, means interpreting ideas expressed by others on drawings, whether or not the drawings are actually blueprints. Drawing or sketching is the universal language used by engineers, technicians, and skilled craftsmen. Drawings need to convey all the necessary information to the person who will make or assemble the object in the drawing. Blueprints show the construction details of parts, machines, ships, aircraft, buildings, bridges, roads, and so forth. BLUEPRINT PRODUCTION Original drawings are drawn, or traced, directly on translucent tracing paper or cloth, using black waterproof India ink, a pencil, or computer aided drafting (CAD) systems. The original drawing is a tracing or “master copy.” These copies are rarely, if ever, sent to a shop or site. Instead, copies of the tracings are given to persons or offices where needed. Tracings that are properly handled and stored will last indefinitely. The term blueprint is used loosely to describe copies of original drawings or tracings. One of the first processes developed to duplicate tracings produced white lines on a blue background; hence the term blueprint. Today, however, other methods produce prints of different colors. The colors may be brown, black, gray, or maroon. The differences are in the types of paper and developing processes used. A patented paper identified as BW paper produces prints with black lines on a white background. The diazo, or ammonia process, produces prints with either black, blue, or maroon lines on a white background. Another type of duplicating process rarely used to reproduce working drawings is the photostatic process in which a large camera reduces or enlarges a tracing or drawing. The photostat has white lines on a dark background. Businesses use this process to incorporate reduced-size drawings into reports or records. The standards and procedures prescribed for military drawings and blueprints are stated in military standards (MIL-STD) and American National Standards Institute (ANSI) standards. The Department of Defense Index of Specifications and Standards lists these standards; it is issued on 31 July of each year. The following list contains common MIL-STD and ANSI standards, listed by number and title, that concern engineering drawings and blueprints.