There are instances where it is acceptable to use only a portion of a feature as a datum feature.

Question

Quizplus · Accepted Answer

It is acceptable to use only a portion of a feature as a datum feature as long as the portion being used is accurately defined and serves the intended purpose of establishing a reference point for measurement or inspection. However, it is important to carefully consider the potential effects on the overall tolerance stack-up and functional requirements of the part.

There Are Instances Where It Is Acceptable to Use Only