Which tolerance uses a datum axis to control the rotation of a feature around the axis?

Which tolerance uses a datum axis to control the rotation of a feature around the axis?

• A. Flatness tolerance
• B. Perpendicularity tolerance
• C. Profile tolerance
• D. Runout tolerance

Answer: (D)

Runout tolerance is all about tying a feature to a datum axis and limiting how that feature can rotate around that axis. When you apply runout, you pick a datum axis and then check the surface as the part is rotated about that axis. The allowed deviation measured in the radial direction tells you how much the feature can wobble or drift away from a perfect circular path while turning, which directly controls rotation around the axis. This specific focus on the relationship between the feature and the axis during rotation is what makes runout the correct choice. Flatness would only address the flat surface’s form, independent of any axis rotation. Perpendicularity sets an angle between a feature and a reference plane or axis but does not govern the rotational motion of the feature about the axis during measurement. Profile defines the outline of a surface, not how that surface behaves as the part rotates around an axis.

Runout tolerance is all about tying a feature to a datum axis and limiting how that feature can rotate around that axis. When you apply runout, you pick a datum axis and then check the surface as the part is rotated about that axis. The allowed deviation measured in the radial direction tells you how much the feature can wobble or drift away from a perfect circular path while turning, which directly controls rotation around the axis. This specific focus on the relationship between the feature and the axis during rotation is what makes runout the correct choice.

Flatness would only address the flat surface’s form, independent of any axis rotation. Perpendicularity sets an angle between a feature and a reference plane or axis but does not govern the rotational motion of the feature about the axis during measurement. Profile defines the outline of a surface, not how that surface behaves as the part rotates around an axis.