Form and Orientation Tolerances Flashcards
7 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 7 Form and Orientation Tolerances flashcards as text
A drawing specifies flatness of 0.05 on a surface that has a size tolerance of ±0.10. Which statement is true?
Answer: The flatness tolerance refines the surface control within the size limits
A flatness tolerance smaller than the size tolerance refines the surface form control; both apply simultaneously and the flatness must be satisfied within the size envelope.
On a sheet-metal bracket, a 0.02 straightness tolerance is applied to the top edge (line element). This means each individual line element along the edge must fit between:
Answer: Two parallel lines 0.02 apart in the plane of measurement
Straightness applied to a surface line element creates a 2D tolerance zone of two parallel lines 0.02 apart within the plane of measurement.
Which of the following orientation tolerances controls a feature at an angle of exactly 0° to a datum?
Answer: Parallelism
Parallelism is the orientation tolerance for a 0° (parallel) relationship between a feature and its datum.
A perpendicularity callout with a diameter symbol (⌀) preceding the tolerance value on an axis means the tolerance zone is:
Answer: A cylindrical zone perpendicular to the datum
The diameter symbol (⌀) before the perpendicularity tolerance value specifies a cylindrical tolerance zone rather than a two-plane zone.
Which GD&T rule states that at Maximum Material Condition (MMC), a feature of size must have perfect form?
Answer: Rule #1 (Envelope Principle / Perfect Form at MMC)
Rule #1, the Envelope Principle, requires that a feature of size must have perfect form (no surface variation) when at its MMC boundary.
When comparing circularity and cylindricity, which statement is accurate?
Answer: Cylindricity evaluates the full 3D surface; circularity evaluates individual cross-sections
Cylindricity controls the entire 3D cylindrical surface at once, while circularity only controls individual 2D circular cross-sections one at a time.
A form or orientation tolerance callout that includes a free-state modifier (F) indicates the measurement should be taken:
Answer: Without any restraining forces applied (in its free state)
The free-state modifier indicates the tolerance applies when the part is in its unrestrained, natural condition without any fixturing forces.