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.
In terms of the tooth thickness, should we use the formulation with
respect to normal or transverse coordinate system? When normalizing
this thickness in order to normalize the backlash (backlash parameter),
we should divide by the circular pitch. Thus, when normalizing, should
this circular pitch be defined in the normal or traverse coordinate
system, depending on which formulation has been used? Is the backlash
parameter always defined with respect to the tangential plane or
normal plane for helical gears?