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 27
ng thepen is spun around by an impulse from the second finger applied atb. The pen is lifted slightly while the needle point is being movedto a new center. Some drop pens have a pencil point that can be in-serted in place of the pen, but most draftsmen draw the pencil circlesfreehand to save time.… … \ ,-Radial Line t (b) Fig. 34.—Railroad curves. the proper radius to represent one certain degree of curvature. Rail-road curves are made of cardboard, wood, hard rubber, celluloid orzinc, a set containing from ten to one hundred curves. Both curvededges are cut to the same radius, and each curve…
Mechanical drawing
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer02inte-390-215.webp)
