Runout and Concentricity 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 Runout and Concentricity flashcards as text
Which datum reference is required for a runout tolerance callout?
Answer: A datum axis
Runout tolerances always require a datum axis because the surface elements are measured relative to rotation about that axis.
A cylindrical surface has a circular runout tolerance of 0.03 mm and is also controlled by a size tolerance of ±0.1 mm. Which statement is correct?
Answer: Both tolerances must independently be satisfied
Size and runout are independent controls; a feature must conform to both its size tolerance and its runout tolerance separately.
Total runout when applied to a cylindrical surface simultaneously controls which combination of errors?
Answer: Cylindricity, coaxiality, and taper
Total runout on a cylinder controls all surface variations including out-of-roundness, wobble, taper, waviness, and coaxiality errors.
A part drawing shows a runout callout with two datum references (e.g., A-B). What does this typically indicate?
Answer: The datum axis is established by two datum features used together
Two datum references for runout typically establish a common datum axis from two separate datum features used simultaneously.
Why is symmetry sometimes used as an alternative to concentricity for symmetric features?
Answer: Symmetry is easier to apply to non-round features than concentricity
Symmetry controls the median points of features relative to a datum plane, making it applicable to non-cylindrical symmetric features where concentricity is not appropriate.
When inspecting total runout on a stepped shaft, how many dial indicator passes are required?
Answer: One pass across the entire controlled surface
Total runout requires the indicator to traverse the entire controlled surface in a single continuous sweep while the part rotates.
A runout tolerance frame contains the symbol for circular runout and the value 0.02. Where is the leader arrow typically directed?
Answer: To the surface being controlled
The feature control frame leader arrow points to the surface being controlled by the runout tolerance, not the datum.