AGMA Historic Accuracy Grades

We get a lot of questions here at AGMA asking for help in decoding gear accuracy grades (also known as tolerance classes). If we’re lucky the inspection standard is called out on the print, or the customer knows what standard they want the gears to be inspected, or they are ok to use the most current standard. If that’s not the case it takes some detective work to determine the proper inspection standard.

I have a table I use as a first step (Page 31) to decode the different accuracy grade designation systems historically used by AGMA. The current designation systems used are highlighted in the table. Looking at letter designations, year published, or type of gear covered columns can help narrow down what standard the designer was thinking of, as long as it’s to an AGMA standard. Tracking down international designations would be another level of complexity. If you need a historic standard to reference for old parts, AGMA maintains an archive of historic standards not on our document store, but available upon email request to tech@agma.org.