. A textbook on mechanical and electrical engineering . Fig. 74 §13 GEOMETRICAL DRAWING 77 Vertical projections of cylinders are shaded as shownin the front elevation of Fig. 5, Drawing Plate, title:Projections—I. After studying the foregoing concerning shade lines, thestudent should be able tosee the reason for the usingor omitting of any shadelines on the drawings in thefollowing plates. In the caseof an object like the hex-agonal prism in Fig. G,Drawing Plate, title: Pro-jections—I, no part of theupper base or line Se isshaded, although, strictlyspeaking, the part ^ ^ of theline should be s
. A textbook on mechanical and electrical engineering . Fig. 74 §13 GEOMETRICAL DRAWING 77 Vertical projections of cylinders are shaded as shownin the front elevation of Fig. 5, Drawing Plate, title:Projections—I. After studying the foregoing concerning shade lines, thestudent should be able tosee the reason for the usingor omitting of any shadelines on the drawings in thefollowing plates. In the caseof an object like the hex-agonal prism in Fig. G,Drawing Plate, title: Pro-jections—I, no part of theupper base or line Se isshaded, although, strictlyspeaking, the part ^ ^ of theline should be shaded; but, as this would make part of thestraight line Sc heavy and the greater part light, the wholeline is drawn light. This is one of the exceptions Fig. MECHANICAL DRAWING Plew. lop I Frohk ce:n^ter liio]S 1. Fig. 1 represents a thick wedge having a cyHndricalhole running through its entire length. The lines inii^pq^and }-s are called centerlines. Center lines are usu-ally drawn through the cen-ter of anything that is round,such as a cylinder or a cylin-drical hole. In the case of acircle, there are usually twocenter lines, one being atright angles to the other, asshown in view />, Fig. drawing two center linesthrough a circle in the man-ner just mentioned, the cen-ter of the circle is located bytheir intersection. The merepresence of these lines showsin most cases that part of theobject through which they are drawn is round. It is veryseldom that center lines appear on drawings unless they arethe center lines of cylindrical surfaces. They may some-times be drawn to indicate that the surface is a regularlycurved surface, such as would be formed by circular arcs, or ? g 14 For notice of copyright, see page immedia
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmechani, bookyear1902
