For Curved Flanks

Rule.—Assume the degree of curve desired for the flanks to be marked, select the corresponding value in the column of “Degrees of flank curving,” and find the tabular value under the number of teeth column.

Multiply tabular value so found by the arc pitch of the teeth, and the product is the setting number on the instrument.

Example.—What is the setting number on the odontograph for the flanks of a wheel to contain 12 teeth and gear with one having 24 teeth, the degree of curvature for the flanks being represented by 4 in the column of “Degree of flank curvature?”

Here in column of degrees of flank curvature on the 3 line and under 12 teeth is .20, which multiplied by pitch of teeth (2) is .20 × 2 = 40, or ⁄10; hence, the fourth line of division on the curved corner is the setting line, it representing ⁄10 of 1.