When a part is touching primary and secondary datum planes and comes in contact with a tertiary plane, it theoretically touches the tertiary plane in ____.
A) four or more points
B) three points
C) two points
D) one point

Question

Quizplus · Accepted Answer

When a part is touching primary and secondary datum planes and then comes in contact with a tertiary plane, it theoretically touches the tertiary plane at one point. This is because the primary datum establishes a plane, the secondary datum establishes a line (requiring two points of contact), and the tertiary datum establishes a single point of contact, ensuring full spatial constraint without over-constraining the part.

When a Part Is Touching Primary and Secondary Datum Planes