Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 60
wing-pen. The outer wheel isrolled on the edge of a T square or straight-edge,and turns a ratchet wheel which causes the pen tomove up and down. The flat point close to thepen must slide on the paper. To change the pat-tern of the dotted lines, the spring which holds thewheels on the axle is thrown… … Fig. 133. Fig. 134. placed beneath. The handle of the ordinary drawing-pen often contains apricking-point, which may be used by unscrewing the pen where it is joined tothe handle. When drawings are transferred by tracing—a prepared black sheet beingplaced between the drawing and the paper to…
Mechanical drawing
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