Go and no-go gauging assumes that the operator applies a defined, small force. In practice operators develop a feel, and feel varies between people and between shifts. The result is that the same lot can be accepted in the morning and rejected in the afternoon without anything about the parts changing.
The convention for hand gauging is that the gauge is applied under its own weight, or with a light push of a few newtons, and that a go gauge which does not enter under that force means rejection. Where the sheet specifies a force, use it. Where it does not, define a local rule, write it into the work instruction, and check that operators can apply it consistently by testing them with a known marginal part.
A simple guided fixture with a weighted plunger converts the judgement into a repeatable one: the gauge either enters under the defined load or it does not. For high volume lines the cost is trivial compared with the cost of a disputed lot, and it also protects the gauge from being forced and worn.
Record the result as pass or fail plus the force method used. If a lot is later disputed, the inspection record is the only evidence, and "operator judged it tight" is not evidence of anything.
