A practical course in mechanical drawing for individual study and shop classes, trade and high schools (1912)
Willard, William Franklin, 1879- · Chicago : Popular mechanics company · leaf 134
con-tour may easily be defined by drawing tangent helicesto these circles. If square or rectangular material isused, draw the helices from each of the four corners,A, B, C, D, of the cross section. Problem 6,—Make a coil spring from 5 roundsteel, 3!/^ inside diameter, i^ pitch and 6 long. Problem… … c D ff IB
Mechanical drawing
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