Babbitt, Arthur B. (Arthur Bradford), b. 1873 · New York, H. Holt and company · leaf 14
Set of drafting instruments Drawing-board—The drawing-board should bemade of soft pine with the left or working edge, theone against which the head of the T square is rest-ing in.Fig. 1, perfectly straight. Care should betaken to use the same side of the board each time,and to have the working edge… … Fig. 1, with the blade extending across the paper.The blade is used as the ruhng edge. 30 °-60 ° triangle—The angles formed by the edgesof this instrument are 30°, 60°, and90° as shown in Fig. 2; hence thename, 30°-60° triangle. Usuallyonly one of the angles is used inreferring to this triangle and…
Mechanical drawing
Internet Archive · University of Connecticut Library · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer02inte-225-114.webp)
