I'm getting old and set in my ways, so like mfgenggear I prefer to use AGMA 2000-A88 if given the choice. The current specs for accuracy classification of cylindrical gears are AGMA 2015-1-A01 (tangential or "A" prefix) and AGMA 2015-2-A06 (radial or "C" prefix). The primary difference between the current and legacy systems for defining accuracy is that the current system requires you to provide a more detailed definition of acceptable tolerance conditions for each individual gear. While the legacy system relied mostly on a set of tables with fixed tolerance values, the current system uses a set of formulas for calculating tolerance values specific to each application. The idea being that using a set of formulas to calculate tolerance values for each specific gear design, rather than simply using values from a set of tables, will improve the quality and/or lower the manufacturing cost of the gear. The downside is that the current approach requires much more effort on the part of engineers, hence the reluctance to embrace it.
Most gear vendors in the US are still very happy to produce gears using the legacy AGMA quality system. But while the current AGMA accuracy system can seem intimidating to those unfamiliar with it, the approach does provide real benefits if used properly.
Good luck with reviewing the specs. They contain a huge amount of technical information to digest.
Terry
