Wallis, Rolland S. [from old catalog], Iowa state college of agriculture and mechanic arts, Ames. Dept. of engineering extension. [from old catalog] · Ames, Iowa, Engineering extension department, Iowa state college · leaf 26
or ruling parallel curved lines with the aid of;i French curve. 23 Railroad Pen.—This instrument (Fig. 33a) is intended for use in rul-ing two parallel lines representing the rails of railroad track, but itlias other uses as well. Curve Pens.—The curve or contour pen (Fig. 33b) is used for… … (»t mm = M V V ic-a (a) (b) (c) (d) (e) Fig. 33.— (a) Railroad pen, (b) curve pen, (c) double curve pen, (d) prickers, (e) drop pen. handle held vertically and the nibs trailing. To work best (on tracingcloth especially) the nibs should be kept sharp so that there is no tend-ency to slip sidewise.…
Mechanical drawing
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