What is a datum target?

• A. A defined point/area used to establish a datum when the datum surface is not readily accessible.
• B. A measurement device used to inspect datums.
• C. A datum feature that must be machined first.
• D. A tolerance zone boundary around datum.

Answer: (A)

A datum target is a defined point or area used to establish a datum when the datum surface isn’t readily accessible. In GD&T, datums provide the reference frame for tolerances, and targets let you locate that reference even if you can’t touch or see the actual datum surface directly. By specifying the size and location of the target, inspectors can consistently reference the intended datum feature.

This isn’t a measurement device, and it isn’t a datum feature that must be machined first, nor is it a boundary for a tolerance zone. It’s a reference construct placed on or near an accessible area to accurately establish the datum.