There are a number of documents dealing with the calibration of thread gages purporting to be “standards” that are really more like training manuals. There is a need out there for this information but invariably, instead of sticking to the metrology involved, they delve into quality decisions and things start to come off the rails.
Some of this material is very well illustrated through drawings and/or photos which makes them more user friendly than comparable recognized standards from which some of their material is derived. However, their recommended practices are often predicated on assumptions that have little or no factual basis and conflict with the purpose of the calibration process.