Elementary mechanical drawing, for school and shop (1886)
Aborn, Frank, 1845- [from old catalog] · Cincinnati, New York, Van Antwerp, Bragg & co · leaf 19
a circumference is an arc of 270degrees, and is written 270°. GEO ME TRICA L DBA WING. 17 One half of a circumference is an arc of 180 de-grees, and is written 180°, etc., etc. A Protractor usedin school work isusually a semicir-cular disk, and-therefore its arccontains 180°. Usu-ally these… … Fig. 11. Prob. 1.—Describe an arc of 60°, with a radius of in. /b Solution.—Describe a cir-cle ABD, | in. in radius.Draw a diameter AD. Placethe protractor on the circleABD, so that its center anddiameter coincide with thecenter and diameter of thecircle, and mark the 60°point, 6, at its edge.…
Mechanical drawing
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
