Iso 2768 Mk Official
The Silent Language of ISO 2768-mK
So use mK for the non-critical. But never forget — The parts that fail in the field are rarely the ones you toleranced tightly. They're the ones you assumed would behave.
But then comes a drawing block labeled:
— straightness, flatness, circularity, cylindricity, parallelism, perpendicularity, symmetry, runout. All the invisible governors that prevent a part from lying about its shape.
Honor it, but don't worship it.
But here's the deep cut:
It works — until it doesn't. Then the CMM doesn't care about your "general note." It only reports: out by 0.03 mm . iso 2768 mk
Because no one checks flatness on every sheet metal bracket. No one validates perpendicularity on a turned shaft — unless the fit screams otherwise.