Size Dimensions to Avoid

In this Question Line video, Jason answers the following question regarding size dimensions to avoid. This question is in response to this recent video: Reporting Size Dimensions with a CMM.

Follow-up from recent video on reporting feature size with CMM, he said we can no longer locate distance between stepped surfaces. Please explain why this is ambiguous, and how to dimension it and report this measurement to get the most direct tolerance between stepped surfaces. There are many applications where precision of stepped surfaces is critical.

In the Reporting Size Dimensions with a CMM video, Jason talked about using point clouds from a CMM to check a size dimension and its tolerance. In that video, he mentioned that the 2018 revision of ASME Y14.5 does not permit locating the distance between stepped surfaces with a size dimension.

In this follow up Question Line video, Jason explains why dimensioning in that way is ambiguous, how utilizing datums and profile eliminates that ambiguous dimension from being applied, and how to report that measurement to get the most direct tolerance between the stepped surfaces.

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