Geometric Dimensioning and Tolerancing (GD&T) Practice Exam 2026 - Free GD&T Practice Questions and Study Guide

The correct choice highlights a significant limitation of implied datums in geometric dimensioning and tolerancing. Implied datums are inferred from the surrounding features of a part rather than explicitly defined. Consequently, when using implied datums, there is often ambiguity regarding the sequence in which various inspection surfaces make contact during measurement. This lack of specification can lead to variability in inspection results because the physical characteristics of the features and their geometry may result in different contact patterns, affecting the part's perceived compliance with specifications.

The distinction between implied and explicitly defined datums is crucial in GD&T, as explicit datums provide clarity and consistency during measurement processes, ensuring accurate assessments of part features. Without a defined order of contact, inspections may yield different interpretations, impacting quality control and overall functionality of the part in its intended application.