In this Question Line video, Jason discusses the following question regarding positional tolerances at MMC: 

What’s the deal with surface interpretation vs axis interpretation??

Drawing and model to explain surface vs axis interpretation for positional tolerance at MMC

 

In this video, Jason reviews the explanation of surface vs axis interpretation for positional tolerance at MMC from ASME Y14.5 section 7. He walks through an example of extreme form error, illustrated in the figure above, showing how these two interpretations can exist on real parts—and why, in these cases, the standard directs us to use the surface interpretation to determine whether the feature passes inspection. 

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