The objective of this report is to determine the origin of the phrase “profile shift.” Several technical books, technical papers, and industrial standards were reviewed for nomenclature associated with profile shift. The phrase “profile shift” translates directly to the German term “Profilverschiebung,” which originated in the last quarter of the 19th century. At first, profile shift was used to avoid undercutting pinions with small numbers of teeth. Later, it was recognized that profile shift improved the load capacity of the gear mesh and extended the service life of manufacturing tools.
A reader asks: We are currently revising our gear standards and tolerances and a few questions with the new standard AGMA 2002-C16 have risen. Firstly,
the way to calculate the tooth thickness tolerance seems to need a "manufacturing profile shift coefficient" that isn't specified in the standard; neither is another standard referred to for this coefficient. This tolerance on tooth thickness is needed later to calculate the span width as well as the pin diameter. Furthermore, there seems to be no tolerancing on the major and minor diameters of a gear.
A reader asks: We are currently revising our gear standards and tolerances, and a few problems with the new standard AGMA 2002-C16 have arisen. Firstly, the way to calculate the tooth thickness tolerance seems to need a "manufacturing profile shift coefficient" that isn't specified in the standard; neither is another standard referred to for this coefficient. This tolerance on tooth thickness is needed later to calculate the span width as well as the pin diameter. Furthermore, there seems to be no tolerancing on the major and minor diameters of a gear.
