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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
  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.