Cyclopedia of architecture, carpentry, and building : a general reference work ... (1907)
American School of Correspondence · Chicago : American Technical Society · leaf 249
as before continue until the desired spiral isobtained, the following curves running parallel to those first drawn.The size of the polygon a\ determines the size of the spiral. In Fig. 143 let A B C D represent the elevation of one cornerof the flag sign shown in Fig. 141. In its proper position in… … Fig. 142. metal, and as the spiral makes two revolutions tBen multiply ^by 14, which would equal 1| inches. Then on E F in Fig 144place the stretchout of the spiral in Fig. 143, as shown by similarnumbers, to which add 17 E equal to 14 times the thickness ofmetal in use, and draw the arc E 17 in…
Architecture · Building · Carpentry
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