How would you evaluate a hole's true position with datums A, B, and C?

• A. It compares the hole's size to a tolerance zone.
• B. It checks runout.
• C. It checks surface roughness.
• D. It evaluates the hole's axis deviation from the true position within the zone defined by A,B,C.

Answer: (D)

When evaluating a hole with datums A, B, and C, you’re checking how far the hole’s axis sits from its intended location in a defined coordinate frame. The datums establish a 3D reference, so the true position is where the hole axis should be if perfectly manufactured. The positional tolerance defines a cylindrical zone around that true position, oriented and located by the datums. To determine acceptability, measure the hole’s axis and see if it lies inside this tolerance zone. If the axis stays within the zone, the hole meets the true position requirement; if not, it’s out of tolerance. This is why the correct approach focuses on the axis deviation from the true position within the zone defined by A, B, and C.