AGMA 08FTM15 PDF

It may not be widely recognized, that most of the inspection data supplied by inspection equipment following the practices of AGMA Standard 2015 and similar standards, are not of Elemental accuracy deviations but of some form of Composite deviations. This paper demonstrates the validity of this "Composite" label by first defining the nature of a true Elemental deviation and then, by referring to earlier literature, demonstrating how the common inspection practices for Involute, Lead (on helical gears), Pitch, and in some cases, Total Accumulated Pitch, constitute Composite measurements. The paper further explains how such measurements often obscure the true nature of the individual deviations. It also contains suggestions as to somelikely source of the deviation in various gear manufacturing processes andhowthat deviationmayaffect gear performance. It further raises the question of the likely inconsistencies of some of these inspection results and of inappropriate judgments of gear quality, even to the point of the rejection of otherwise satisfactory gears. Finally, there are proposals for modifications to inspection software, possibly to some inspection routines, all to extending the benefits of the basic Elemental inspection process.