GD&T Material Condition Modifiers 2

Question 1

A shaft has a true position tolerance of 0.2 MMC. At MMC the shaft diameter is 20.0 mm. If the shaft is produced at 19.8 mm, what is the total allowable position tolerance?

Accepted Answer

0.4 mm

Answer

The shaft has departed 0.2 mm from MMC, so the bonus tolerance (0.2) is added to the stated tolerance (0.2), giving 0.4 mm total.

Question 2

Which material condition modifier requires the tolerance zone to remain fixed regardless of the feature's actual size?

Accepted Answer

RFS

Answer

RFS (Regardless of Feature Size) means the specified tolerance applies at every actual mating size with no bonus tolerance.

Question 3

On an internal feature (hole), the LMC condition corresponds to which of the following?

Accepted Answer

Smallest allowable hole diameter

Answer

For a hole (internal feature), LMC is the smallest diameter because that represents the least material removed.

Question 4

The virtual condition of an external feature controlled at MMC is calculated as:

Accepted Answer

MMC size plus the geometric tolerance

Answer

For an external feature (e.g., shaft) at MMC, the virtual condition = MMC size + geometric tolerance, representing the worst-case boundary.

Question 5

Which modifier, when applied to a datum feature, allows the datum to shift as the feature departs from its referenced material condition?

Accepted Answer

MMC on a datum reference

Answer

Applying MMC (or LMC) to a datum reference in a feature control frame allows datum shift equal to the departure from that material condition.

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

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

GD&T Material Condition Modifiers 2