That appears to be a Go/No-Go gage. Take, for example a part that has an OD tolerance of .250” +/- .010” You’d set the height of the two “upper” jaws such that the jaw closer to the open side is at .2601” and the 2nd jaw to .2399”. The part must Go through the first jaw and No-Go through the 2nd jaw. Quick way to check high-volume parts for a pass/fail condition when you don’t want to spend time using a micrometer on every part.Of course! As with many mystery tools, once you know the answer you wonder how you did not identify it immediately! Leave it to the FJ40 Land Cruiser-owning Cajun philosopher!
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