“It appears that undercut can be eliminated in some cases but in most cases, the elimination of undercut, for example by increasing the root fillet radii of a pinion, results in performance problems in the operation with its mate. My question is, when can I eliminate undercut and why is it not possible in most cases?”
Question: When evaluating charts from a gear inspection machine, it is sometimes found that the full length of the profile traces vary, and that sometimes they are less than the length of active profile (above start of active profile-SAP) by up to 20%. This condition could be caused by a concentricity error between tooth grinding and shaping, or by unequal stock removal when grinding. (See Fig. 1.) Is it possible that some of the variation is coming from the inspection machine? How can variation from the inspection machine be reduced?
