GD&T ASME Y14.5 Standards and Drawing Interpretation Flashcards
6 cards from real GD&T practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 GD&T ASME Y14.5 Standards and Drawing Interpretation flashcards as text
Which standard governs GD&T practices in the United States?
Answer: ASME Y14.5
ASME Y14.5, published by the American Society of Mechanical Engineers, is the U.S. standard defining GD&T symbols, rules, and practices.
What does Rule #1 (the Envelope Principle) state in ASME Y14.5?
Answer: A feature of size's surface must not violate a perfect-form envelope at MMC
Rule #1 requires that a feature of size controlled only by size tolerances must not violate a perfect-form (zero geometric error) boundary when the feature is at MMC.
What is a 'feature of size' as defined by ASME Y14.5?
Answer: A feature with directly opposed elements — such as a cylinder, hole, or two parallel surfaces — definable by a single size dimension
A feature of size has directly opposed surfaces or elements that can be measured across a single dimension, enabling MMC and LMC modifiers to apply.
What does ASME Y14.5 Rule #2 establish?
Answer: Unless otherwise specified, all geometric tolerances apply at RFS (Regardless of Feature Size)
Rule #2 makes RFS the default condition — if no modifier is shown in the feature control frame, the geometric tolerance applies at all feature sizes.
What major new symbol was introduced in the ASME Y14.5-2018 revision?
Answer: The Independent modifier (encircled I), which overrides Rule #1 for a specific feature
ASME Y14.5-2018 introduced the Independent modifier (Ⓘ), which explicitly releases a feature from Rule #1's perfect-form-at-MMC requirement.
Under ASME Y14.5, what is the default geometric tolerance condition when no modifier is shown?
Answer: Regardless of Feature Size (RFS)
Per Rule #2, RFS is the default — the geometric tolerance zone is fixed at the stated value regardless of the feature's actual produced size.