Working Drawings of Machinery (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1913 Excerpt: ... regular detail drawing for permanent use is the complete detail drawing accurately made, with proportions correct, and finished up in such a manner that copies can be easily and cheaply made without injury to the original. When the term " detail drawing" is used, it is ordinarily understood to refer to the drawing as above described. There are two stages in the production of such a drawing: first, the preliminary drawing ordinarily spoken of as the pencil drawing; second, the final drawing almost always in ink, made either by inking over the lines on the pencil drawing, if that is made on suitable material, or by covering the pencil drawing with tracing cloth and tracing the lines in ink. Sometimes when the drawing is for temporary use, the pencil drawing is used as the final drawing and blue prints are made from it. For convenience we will refer to the preliminary drawing as the pencil drawing and the final as the ink drawing. Since it is the ink drawing from which copies are taken for shop or other uses, and the pencil drawing is only a stage in the making of the ink drawing, our discussion will naturally apply to the final drawing unless the pencil drawing is specifically mentioned. Drafting Room Systems. We have already referred to the fact that each drafting room adopts its own system in the matter of methods of representing, dimensioning, conventional signs, and the like. In addition to this some system is essential in the matter of size of sheets on which the drawings are made, position and content of titles, numbering, filing, etc. A systematic method for making and recording alterations of the drawing is also of vital importance. It would hardly be profitable for us here to describe in detail any one of the systems in use. A general disc...