By JOHN S. REID, Sr., Mem.A.S.M.E. Assistant Professor of Mechanical and Elementary Machine Drawing, FIRST EDITION NEW YORK JOHN WILEY & SONS, INC. LONDON: CHAPMAN & HALL, LIMITED re PREFACE A MECHANICAL DRAWING is used to convey precise information from one person to another. A patternmaker must have a true drawing of an object, giving correct dimensions and instructions before he can make a pattern, from which the foundryman can make a rough casting. The machinist must have a drawing from which he can obtain accurate information to enable him to take the rough casting and by slotting, planing, drilling, grinding, chipping or turning he can produce the finished article as designed by the draftsman. Contractors, builders, architects, and engineers of all kinds, must have accurate drawings to enable them to produce satisfactory results in their work. To do this it is essential that working drawings should be made according to certain principles and methods thoroughly understood by the man who makes the drawing and the man who uses it. This volume on Mechanical Drawing is a fundamental course embodying all the theory, principles, and methods necessary to enable the student to make a practical working drawing. Considering Mechanical Drawing as a language to convey thoughts and ideas; orthographic projection, which is a division of descriptive geometry, is its grammar and the foundation upon which is built all kinds of correct mechanical drawings. This course is the result of twenty-five years of experience in teaching Mechanical Drawing and Elementary Machine Drafting (fifteen years at Cornell University and nearly eleven years at Armour Institute of Technology, besides Summer School 410876 |