Babbit, Arthur B · New York, H. Holt and company · leaf 14
MATERIAL … 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 · 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-225-114.webp)
