. A textbook on mechanical and electrical engineering . ave about ^ or f of an inch of the lead projecting; then sharpen it flat by rubbing it against a fine file or a piece of GEOMETRICAL DRAWING 11 fine emery cloth or sandpaper that has been fastened to aflat stick. Grind it to a sharp edge like a knife blade, andround the corners very slightly, as shown in the figure. Ifsharpened to a round point, as shown at B, the point willwear away very quickly and make broad lines; when sosharpened it is difficult to draw a line exactly through apoint. The lead for the compasses should be sharpe
. A textbook on mechanical and electrical engineering . ave about ^ or f of an inch of the lead projecting; then sharpen it flat by rubbing it against a fine file or a piece of GEOMETRICAL DRAWING 11 fine emery cloth or sandpaper that has been fastened to aflat stick. Grind it to a sharp edge like a knife blade, andround the corners very slightly, as shown in the figure. Ifsharpened to a round point, as shown at B, the point willwear away very quickly and make broad lines; when sosharpened it is difficult to draw a line exactly through apoint. The lead for the compasses should be sharpened inthe same manner as the pencil, but should have its widthnarrower. Be sure that the compass lead is so secured thatwhen circles are struck in either direction, but one line ivillbe draxvn with the same radius and center. 13. Inking.—For drawing ink lines other than arcs ofcircles, the ruling pen (or right-line pen, as it is sometimescalled) is used. It should be held as nearly perpendicularto the board as possible, with the hand in the position. Fig. 15 shown in Figs. 15 and 16, bearing lightly against the T squareor triangle, along the edge of which the line is a little practice, this position will become natural, andno difficulty will be experienced. 12 GEOMETRICAL DRAWING 13 1-4. The beginner will find that it is not always easy tomake smooth lines. If the pen is held so that only one bladebears on the paper when drawing, the line will almost inva-riably be ragged on the edge where the blade does not held at right angles to the paper, as in Fig. 16, how-ever, both blades will rest on the paper, and if the pen is ingood condition, smooth lines will result. The pen must notbe pressed against the edge of the T square or triangle, asthe blades will then close together, making the line edge should serve as a guide simply.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectmechani, bookyear1902
