A textbook on mechanical and electrical engineering (1902)
International Correspondence Schools · Scranton : International Textbook Co. · leaf 62
equalparts (in this case 12), and divide the circle into the same 13 GEOMETRICAL DRAWING 47 number of equal parts, beginning at one extremity of thediameter 12 O 6, drawn parallel to B E. At the point 1 onthe circle divisions, erect I-l perpendicular to B E\ throughthe point 1 of the pitch… … So proceed until the point 6 is reached; from here on, untilthe point 12 of the helix is reached, the curve will be dotted.It will be noticed that the points of division 7, 8\ 9, 10,and 11 on the circle are directly opposite the points f/, 4,3, 2, and T ; hence, it was not necessary to draw the…
