GD&T Form and Orientation Tolerances 5

Question 1

A drawing specifies flatness of 0.05 on a surface that has a size tolerance of ±0.10. Which statement is true?

Accepted Answer

The flatness tolerance refines the surface control within the size limits

Answer

A flatness tolerance smaller than the size tolerance refines the surface form control; both apply simultaneously and the flatness must be satisfied within the size envelope.

Question 2

On a sheet-metal bracket, a 0.02 straightness tolerance is applied to the top edge (line element). This means each individual line element along the edge must fit between:

Accepted Answer

Two parallel lines 0.02 apart in the plane of measurement

Answer

Straightness applied to a surface line element creates a 2D tolerance zone of two parallel lines 0.02 apart within the plane of measurement.

Question 3

Which of the following orientation tolerances controls a feature at an angle of exactly 0° to a datum?

Accepted Answer

Parallelism

Answer

Parallelism is the orientation tolerance for a 0° (parallel) relationship between a feature and its datum.

Question 4

A perpendicularity callout with a diameter symbol (⌀) preceding the tolerance value on an axis means the tolerance zone is:

Accepted Answer

A cylindrical zone perpendicular to the datum

Answer

The diameter symbol (⌀) before the perpendicularity tolerance value specifies a cylindrical tolerance zone rather than a two-plane zone.

Question 5

Which GD&T rule states that at Maximum Material Condition (MMC), a feature of size must have perfect form?

Accepted Answer

Rule #1 (Envelope Principle / Perfect Form at MMC)

Answer

Rule #1, the Envelope Principle, requires that a feature of size must have perfect form (no surface variation) when at its MMC boundary.

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

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

GD&T Form and Orientation Tolerances 5