GD&T Material Condition Modifiers 5

Question 1

Which statement correctly compares the virtual condition of a hole controlled at MMC versus the same hole controlled at LMC?

Accepted Answer

The MMC virtual condition is a smaller (tighter) inner boundary than the LMC virtual condition

Answer

For a hole at MMC, virtual condition = MMC size − tolerance (smallest inner boundary); at LMC, resultant condition uses LMC − max tolerance, but virtual condition at LMC = LMC + tolerance (largest outer boundary), serving a different purpose.

Question 2

A position tolerance is given as 0.0 Ⓜ in a feature control frame. What does this indicate?

Accepted Answer

No positional error is allowed unless the feature departs from MMC, then bonus tolerance becomes available

Answer

A zero MMC tolerance means perfect position at MMC, but bonus tolerance accumulates as the feature departs from MMC, allowing positional error proportional to size departure.

Question 3

Under ASME Y14.5, which of the following tolerances CAN be legally modified with LMC?

Accepted Answer

True Position of a hole

Answer

True position references a feature of size (the hole), so LMC is applicable; surface-only controls like flatness, circularity, and surface parallelism cannot use material condition modifiers.

Question 4

When inspecting a feature using a functional (hard) gauge designed for an MMC position callout, a part that passes the gauge is considered:

Accepted Answer

Acceptable for the virtual condition boundary requirement only; size still needs separate verification

Answer

A functional gauge verifies the virtual condition (worst-case boundary) but does not verify the size tolerance, which requires a separate attribute or variable measurement.

Question 5

An engineer wants to ensure a minimum edge distance is maintained as a hole's position shifts. Which modifier applied to the position tolerance would best protect edge distance?

Accepted Answer

LMC — provides tighter positional control when the hole is at its largest (least material)

Answer

LMC tightens position control as the hole grows larger (less edge material), protecting minimum edge distance at the worst-case scenario.

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

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

GD&T Material Condition Modifiers 5