Machine drawing; a practical guide to the standard methods of graphical representation of machines, including complete detail drawings of a duplex pump and of a direct-current generator . the firstthing to do is to lay out the sheet. The standard sheet for detailswhich has been adopted is 18X24 inches trimming size, with |-inchmargin all round, so that the working space is 17x23 inches. Therectangle for the title is to be laid off 2|X4 inches in the lower right-hand corner, and must never be altered, either in size or does not mean that other sizes are wrong, but once a standards
Machine drawing; a practical guide to the standard methods of graphical representation of machines, including complete detail drawings of a duplex pump and of a direct-current generator . the firstthing to do is to lay out the sheet. The standard sheet for detailswhich has been adopted is 18X24 inches trimming size, with |-inchmargin all round, so that the working space is 17x23 inches. Therectangle for the title is to be laid off 2|X4 inches in the lower right-hand corner, and must never be altered, either in size or does not mean that other sizes are wrong, but once a standardsystem is adopted it must be strictly adhered to, both for artisticand commercial reasons. The scale to which the drawing is to bemade is indicated in the title corner on every plate. Scales to be Used. The scales permissible for shop drawingsin the United States are those readily derived from the common footrule, such as full size, 6 inches = 1 foot, 3 inches = 1 foot, 1J inches= 1 foot. These are the most common, most easily read from anordinary scale, and one of these can usually be adopted. Thestudent should learn to read these from an ordinary scale without 172 MACHINE DRAWING. MACHINE DRAWING 173 being confined to a special graduation. To do this it is not neces-sary to divide each dimension by 2, 4, and 8 to get half size, quartersize, or eighth size, and then lay down the result. For half size, or6 inches = 1 foot, f inch on an ordinary rule represents 1 , each half inch may be read as 1 inch, and its subdivisions 2 accordingly, thus: For 3 inches = 1 foot, or quarter llllllllllllllll 0 12 3 size, \ inch represents 1 inch, and looks thus: i I i For 1J inches = 1 foot, or eighth size, f inch represents 1 inch, and looks thus: 0 Nihil It is very easy to get accustomed to this, and it saves much time and trouble hunting up a special scale every time. The other allowable scales, less common, but sometimes neces-sary on large work, are 1 inch = 1 foot, f inch =
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Keywords: ., bookcentury1900, bookdecade1910, bookpublis, booksubjectmachinery
