Elements of general drafting for mechanical engineers

This book is intended, by a representative course of progressive exercises found in the two hundred hour Course in Drawing in the first part of the book and by a systematically arranged compilation of precept found in the Manual of Drawing in the second part of the book, to convey the essentials of modem conventional drafting as practiced by the general profession of mechanical engineering.

The Course in Drawing is divided for convenience into five grades: The drawings of the first grade are to be practically copies of the four assigned plates and are to be made from detailed instructions in procedure. The object of the work in this grade is to give the student the science of the elementary principles of drafting and instruction in the use of the materials and instruments and in the technic involved. The drawings of the second grade are to be detailed working drawings made from sketches of machine parts. — One of the most important acquirements for a draftsman is to be able to sketch machine details neatly, accurately and with facility; and, for a student, hardly anything is more interesting and instructive than working from something that has definite form and utility and, incidentally, a large amount of the form of good design may be acquired by absorption. The drawings of the third grade are to be assembly drawings made from sketches of machine parts. The drawings of the fourth grade are to be detailed working drawings and detailed assembly drawings from plates which are copies of commercial drawings.

It is excellent practice for a student to analyze drawings of standard machines and their parts in order to acquire facility in picturing in his mind the shape and proportions of the piece drawn. The drawings of the fifth grade are foundation drawings with their bolt templets, floor plans, and Patent Office drawings. These drawings are in a distinct class by themselves, and conventions employed in their execution should be understood by all well equipped draftsmen, and a knowledge of the technic involved in Patent Office drawing is invaluable for any one whether he be layman or draftsman.

The drawing course has been extended by the addition of plates of complete detail drawings of a 15" Pillar Shaper which are to be used in making assembly drawings. These plates are copies of a standard commercial machine

The Manual of Drawing describes the selection, use, and care of materials and instruments and all the essential technic employed in the execution of a complete commercial drawing. The object of the Manual is to put into definite form a single and standard drafting room system which shall be the average of the systems used by representative manufacturing concerns. For this purpose, data have been acquired from one hundred and thirty of the largest concerns in the United States in various lines of business.

Illustrations by line-cuts and half-tones are freely distributed through the Manual to make clear the important points discussed in the text. In addition, twenty-one 9X12 zincograph plates are bound into the back part of the book to accompany the Course in Drawing.

An 8X11 pocket in the inside of the back cover of the book is provided for holding loose sketches and any detached material that may be used in connection with the book.

This book is specifically written for the use of the students in drawing in the present Sophomore class of Sibley College, for students in manual training schools, trade schools, and technical colleges, and for the amateur draftsman who is serving his apprenticeship.

The authors desire to thank all the manufacturing concerns who have so kindly lent assistance by contributing drawings and data.

The first nineteen zincograph plates in the back part of the book were made from copies of drawings executed by Mr. Freeman.