GD&T Form and Orientation Tolerances 3

Question 1

What does it mean when a straightness tolerance is applied to the derived median line of a shaft rather than its surface?

Accepted Answer

Rule #1 is overridden and the shaft axis may bow outside the MMC boundary

Answer

Straightness of the derived median line overrides Rule #1, allowing the axis to bend outside the perfect-form-at-MMC boundary while the shaft remains within size limits at each cross-section.

Question 2

A parallelism tolerance of 0.05 mm applied to a surface means the surface must lie between two planes that are parallel to the datum and separated by:

Accepted Answer

0.05 mm

Answer

The tolerance value of 0.05 mm directly defines the width of the tolerance zone between the two parallel planes.

Question 3

Which orientation tolerance would you use to ensure a drilled hole is exactly 90° to a datum surface?

Accepted Answer

Perpendicularity

Answer

Perpendicularity is the orientation tolerance specifically defined for 90° relationships between a feature and a datum.

Question 4

On a GD&T drawing, a circularity tolerance of 0.02 applied to a sphere means:

Accepted Answer

Every cross-section through the center must have a roundness within 0.02

Answer

Circularity on a sphere requires every cross-section passing through the center to be circular within the tolerance value.

Question 5

Which of the following best describes the cylindricity tolerance zone?

Accepted Answer

Two coaxial cylinders between which the surface must lie

Answer

Cylindricity's tolerance zone consists of two coaxial (same-axis) cylinders; the entire surface must fall between them.

(GD&T) Geometric Dimensioning and Tolerancing Certification Practice Test

(GD&T) Geometric Dimensioning and Tolerancing Certification Practice Test

GD&T Form and Orientation Tolerances 3