Mechanical drawing self-taught: comprising instructions in the selection and preparation of drawing instruments. Elementary instruction in practical mechanical drawing. Together with examples in simple geometry and elementary mechanism, including screw threads, gear wheels, mechanical motions, engines and boilers (1889)
Fig. 92. Section shading or cross-hatching may sometimescause the lines of the drawing to appear crooked tothe eye. Thus, in Figure 92, the key edge on theright appears curved inwards, while on the left SHADOW LINES AND LINE SHADING. 81 the key edge appears curved outwards, although suchis not… … Fig- 93-in Figure 93 on the right-hand edge of the key, butnot on the left-hand ed^e.
Mechanical drawing
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