The Sheet metal worker's instructor : for zinc, sheet iron, copper, and tin plate workers, and others, containing a selection of geometrical problems, also practical and simple rules for describing the various patterns required in the different branches of the above trades (1906)
Warn, Reuben Henry · Philadelphia : Henry Carey Baird & Co. · leaf 261
e radius with which the outside of template is to be drawn, is 1497*6 inches, it would be inconvenient to draw a circle with a radius of that length by the common mode; therefore some other method has to be adopted for finding the curve; the one usually taken is to calcu- late the versed line… … In the right angled triangle E B G, is given E B = 1497-6 in., BG-= 5-^-^1^ = 28-2744 inches. Then E B2— B G2 is= E ; hence E G^ can be found, and consequently the versed line.
Sheet-metal work
Internet Archive · Getty Research Institute · Public domain (published before 1931). Free to use for anything.
