Geometric Symbols & Notation Flashcards
7 cards from real GD&T practice questions. Tap to flip, then mark Knew It or Still Learning โ missed cards come back until you master them.
Read the first 7 Geometric Symbols & Notation flashcards as text
What does the 'independency' symbol (circled I) indicate when applied to a feature of size?
Answer: The size and form tolerances are independent and do not interact
The independency symbol overrides Rule #1 (perfect form at MMC), allowing the form tolerance to be independent of the size tolerance.
A GD&T 'Symmetry' callout controls:
Answer: The location of a feature's median plane relative to a datum plane
Symmetry (removed in ASME Y14.5-2009, retained in ISO) requires that the median points of a feature lie within a tolerance zone centered on a datum plane.
On a GD&T drawing, a dimension value enclosed in a rectangular box (no text) signifies:
Answer: A basic (theoretically exact) dimension
A boxed dimension value (without the word BASIC) is the ISO method for denoting a theoretically exact basic dimension.
The 'Least Material Condition' (LMC) modifier circled L is used to:
Answer: Apply additional tolerance when a feature is at its minimum material condition
The LMC modifier allows a geometric tolerance to increase as the feature departs from its least material condition, useful for ensuring minimum wall thickness.
Which symbol on a feature control frame indicates a 'simultaneous requirement' is not in effect and features are verified independently?
Answer: SEP REQT (Separate Requirement) notation
Adding 'SEP REQT' (Separate Requirement) to a feature control frame means each callout is gauged independently rather than simultaneously.
In GD&T notation, a 'statistical tolerance' symbol (circled ST) means:
Answer: The tolerance is assigned based on statistical process control and may only be used in statistical sampling inspection
A statistical tolerance callout indicates that the tolerance is larger than it would be conventionally, justified by statistical process control methods that ensure assembly function.
The 'Profile of a Line' symbol controls:
Answer: The shape of a cross-sectional slice of a surface at a single cutting plane
Profile of a Line (single arc symbol) applies the profile tolerance to each individual 2D cross-section independently, not to the whole 3D surface.