GD&T - Geometric Dimensioning and Tolerancing Runout and Concentricity Questions and Answers

Question 1

An engineer is designing a high-speed rotating shaft that must have minimal vibration.
It is critical that the entire cylindrical surface of the shaft remains straight, round, and coaxial with the bearing journals (datums).
Which GD&T control is most appropriate to apply to the main body of the shaft?

Accepted Answer

Total Runout

Answer

Circularity

Answer

Cylindricity

Answer

Concentricity

Question 2

Which of the following statements best describes the primary difference between circular runout and total runout?

Accepted Answer

Total runout requires a 3D tolerance zone and controls the entire surface, while circular runout uses a 2D zone and controls each circular element independently.

Answer

Circular runout can use an MMC modifier, while total runout cannot.

Answer

Circular runout controls the entire surface at once, while total runout controls individual cross-sections.

Answer

Total runout controls only the location of an axis, while circular runout controls only the form of a surface.

Question 3

When inspecting a part, which of the following is a key difference in methodology between measuring Concentricity and measuring Runout?

Accepted Answer

Runout is measured by finding the full indicator movement (FIM) on a surface, while Concentricity requires deriving an axis from the median points of the feature.

Answer

Concentricity is measured by finding the full indicator movement (FIM) of a surface, while Runout requires deriving an axis from median points.

Answer

Runout can only be applied to external features, while Concentricity can be applied to both internal and external features.

Answer

Concentricity is always applied at MMC, while Runout is always applied at RFS.

Question 4

A feature control frame specifying total runout is applied to the face of a flange that is perpendicular to a central datum axis. What does this tolerance control?

Accepted Answer

The cumulative variation of perpendicularity and flatness of the flange face.

Answer

Only the flatness of the flange face, independent of the datum axis.

Answer

Only the perpendicularity of the flange face to the datum axis.

Answer

The coaxiality of the flange face's outer diameter to the datum axis.

Question 5

According to the ASME Y14.5 standard, what is the shape of the tolerance zone for a concentricity control applied to a cylindrical feature?

Accepted Answer

A cylinder whose axis is theoretically coincident with the datum axis.

Answer

Two parallel planes perpendicular to the datum axis.

Answer

Two coaxial circles at each cross-sectional measurement plane.

Answer

A sphere centered on a datum point.

Question 6

When total runout is applied to a cylindrical surface relative to a datum axis, it controls the cumulative effect of which geometric variations?

Accepted Answer

Circularity, straightness, coaxiality, and taper.

Answer

Circularity and Profile of a Line only.

Answer

Coaxiality and Perpendicularity only.

Answer

Straightness and Flatness only.