Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 332
ed that the wheel shall contain. In a line with such number of teethtake from columns 2, 3, 4, 5, and 6 the numbers that are in them ; and inevery case multiply such numbers by the pitch. The products will be thenumber of inches and parts of inches to which the compasses must be openedto describe… … Seek in column 1 for 30, the number of proposed teeth, and take from col-umn 2 the numbers 4o-78, which multiplied by 2|- inches, the product will be11^957. Open the compasses, therefore, to this radius and describe a circle,which will be the pitch-circle. On an arc of this circle lay off 2^5 X 48…
Mechanical drawing
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