Kenat:
You asked me what I thought of the checking fixture or method expressed by your Tec-Ease attachment in your original post. Tec-Ease usually have pretty good examples but this one is not at the top of the list. As a matter of fact, this example might be flawed. If a Toolmaker was given the drawing of the gauge, could he/she make the gauge? Not really!
The Tec-Ease gauge design does not show whether a full diameter or a threaded diameter pin would be inserted in each of the two (2) holes. It is a threaded diameter that should bottom out on surface datum A so the gauge pin thread length would be 10.2 mm. If the FCF does not state "MINOR DIA" then it is its axis derived from the pitch cylinder. (Screw Threads 2.9 - ASME Y14.5-2009 & 94). JP - I believe that it is its pitch cylinder rather than a theoretical one.
The full diameter that should protrude through the 15 mm projection is shown here in the Tec-Ease example is 10 mm. That makes sense but it would not make any difference whether we use 10 mm or, maybe, 12 mm. The gauge hole for the projection would be a diametrical tolerance zone 0.8 mm beyond either 10 mm or 12 mm. In the Tec-Ease example, it is a diameter of 10.8 mm. In our Tec-Ease example, one would have to insert each of the two (2) threaded pins through the projection plate (15 mm thick) and then thread the ends all the way down into the threaded holes until they contact against datum A surface. This simulates assembly. If either of the pins does not thread in the holes, the part is nonconforming.
There should also be hard pins in both datum B and C holes of virtual condition size, shape and orientation in the case of the slot.
If I were a Designer (and I'm not), I would place "MINOR DIA" under the feature control frame of a pattern of threaded holes as long as there was not a projection of an sort. A hard gauge of the minor diameter's virtual conditional size would be made and we would treat the threaded holes as plain holes. It is pretty easy to check on the shop floor.
If we had a projection value of any sort, I would not use "MINOR DIA" under the FCF but still reflect it in MMC such as the Tec-Ease example.
Dave D.