The sheet-metal worker's guide : a practical handbook for tinsmiths, coppersmiths, zincworkers, etc., comprising numerous geometrical diagrams and working patterns, with descriptive text (1888)
Crane, W. J. E. (W. J. Eden) · London : Lockwood and Son · leaf 60
48 THE SHEET-METAL WORKER's GUIDE. centre, and any radius, describe tlie arc 3 ; with the opposite point as centre, and the same radius, cut the arc 3 at 2. Join b 2, and the line b 2 will bisect the angle A b c — that is to say, the angle a b 2 will be equal to the angle 2 b c. To trisect (divide… … B C Fig. 43. and any radius, describe the arc 2 ; with the centres 1 and 2, and the same radius, describe the arcs 3 and 4. Draw b 3 and b 4, and the right angle will be trisected or divided into three equal angles. In a given circle to inscribe any regular polygon, say a pentagon. One method : —…
Sheet-metal work
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