GD&T Virtual Condition and Boundary Concepts Flashcards

What is the relationship between virtual condition and bonus tolerance?

Answer: Virtual condition is a fixed boundary while bonus tolerance increases as the feature departs from MMC

Virtual condition is constant (MMC ± geometric tolerance), whereas bonus tolerance is a variable that grows as the feature departs from MMC toward LMC.

For a clearance-fit assembly, which comparison guarantees that all conforming parts will assemble?

Answer: The pin's virtual condition must be less than or equal to the hole's virtual condition

Parts always assemble when the pin's virtual condition (worst-case largest) is no bigger than the hole's virtual condition (worst-case smallest).

Under RFS (Regardless of Feature Size), which boundary concept applies?

Answer: Neither virtual condition nor resultant condition — the stated tolerance applies at every size

Under RFS there is no bonus tolerance and no virtual/resultant condition boundary; the geometric tolerance zone is fixed at the stated value regardless of actual feature size.

A pin has a virtual condition of 12.3 mm. What is the minimum hole virtual condition required to guarantee assembly?

Answer: 12.3 mm or larger

The hole's virtual condition must be ≥ 12.3 mm so that the worst-case pin always fits inside the worst-case hole.

Which ASME Y14.5 calculation is expressed as (MMC + perpendicularity tolerance) for a shaft?

Answer: Virtual condition

For a shaft, virtual condition = MMC + perpendicularity (or other form/orientation/position) tolerance at MMC.

When is it most appropriate to invoke the LMC modifier instead of MMC on a hole?

Answer: When the design concern is minimum wall thickness or edge distance rather than assembly clearance

LMC is chosen when the critical design concern is preserving enough material at the edge of a hole, not the assembly clearance.