Detroit Section Paper - Since a gear is a product of the cutting tool, the gear-cutting machine and the operator, it can be no more accurate than the combined accuracy of these fundamental factors. All gear manufacturers aim to eliminate split bearings, high and low bearings, flats and other inaccuracies in tooth contour, because a gear having teeth the contours of which comply with the geometrical laws underlying its construction is by far the most satisfactory.
Illustrations are presented to convey an understanding of the geometrical principles involved, together with other illustrations of testing instruments and comments thereon. The application of these instruments is termed quality control, which is discussed in some detail under the headings of hob control, machine control and gear control. The author states that these testing instruments enable a gear manufacturer to know what results he obtains with gears, hobs and machines, and thus assist in the securing of a uniform product.