GD&T Form and Orientation Tolerances 4

Question 1

A feature control frame shows perpendicularity with an MMC modifier (Ⓜ) applied to a pin. As the pin's actual size departs from MMC, the perpendicularity tolerance:

Accepted Answer

Increases by the same amount as the departure

Answer

The MMC modifier creates a bonus tolerance: for each unit the pin departs from MMC toward LMC, the perpendicularity tolerance increases by one unit.

Question 2

Which GD&T control is most appropriate to ensure two mating flat surfaces will make full contact (not rock)?

Accepted Answer

Flatness

Answer

Flatness controls how planar a single surface is, preventing rocking or wobble when two surfaces are mated.

Question 3

Under ASME Y14.5-2018, which modifier can be applied to straightness of a derived median line to allow additional tolerance?

Accepted Answer

Maximum Material Condition (MMC) or Least Material Condition (LMC)

Answer

Straightness of a derived median line may use MMC or LMC modifiers to grant bonus tolerance as the feature departs from the specified material condition.

Question 4

A parallelism callout of 0.1 on a surface with datum A means the surface must:

Accepted Answer

Lie between two planes 0.1 apart and parallel to datum A

Answer

Parallelism creates a tolerance zone of two parallel planes separated by the tolerance value, both parallel to the referenced datum.

Question 5

When a perpendicularity tolerance is applied to a flat surface (not an axis), which modifier is NOT applicable?

Accepted Answer

Maximum Material Condition (MMC)

Answer

MMC and LMC modifiers apply only to features of size (axes or center planes), not to surfaces; perpendicularity on a flat surface cannot use MMC.

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

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

GD&T Form and Orientation Tolerances 4