Practice Test Geeks(GD&T) Geometric Dimensioning and Tolerancing Certification Practice Test
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Surface Finish & Assembly Requirements 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 Surface Finish & Assembly Requirements flashcards as text

  1. A threaded fastener hole drawing calls out a perpendicularity tolerance of 0.1 mm for the hole axis relative to the mounting surface. This ensures:

    Answer: The bolt will not induce bending stress on the mating flange

    Perpendicularity of the threaded hole to the mounting surface ensures the bolt pulls straight, preventing bending moments that could cause fatigue failure in the flange.

  2. What does the sampling length (cutoff wavelength λc) determine in surface roughness measurement?

    Answer: The wavelength boundary separating roughness from waviness

    The cutoff wavelength λc is a filter setting that separates short-wavelength roughness from longer-wavelength waviness in surface measurements.

  3. A sealing surface for an O-ring groove must have Ra between 0.8 μm and 1.6 μm. A measured Ra of 0.4 μm would be:

    Answer: Out of tolerance because it falls below the minimum Ra

    O-ring grooves require a minimum roughness so the elastomer can grip the surface; a surface that is too smooth can allow the O-ring to extrude or roll out.

  4. In ASME Y14.5, which condition applies when a feature of size is at its maximum material condition (MMC) and a geometric tolerance is at its least restrictive?

    Answer: Maximum Material Condition (MMC) modifier (circle M)

    The MMC modifier (⊕M) allows the geometric tolerance to increase as the feature departs from MMC toward LMC, providing bonus tolerance for assembly clearance.

  5. A component drawing requires a surface finish of Ra 0.8 μm on a mating face. The manufacturing engineer proposes lapping instead of grinding. This is acceptable if:

    Answer: Lapping can achieve Ra 0.8 μm and no process restriction is noted

    Without a specified process restriction on the surface symbol, any process that achieves the required Ra value is acceptable per drawing intent.

  6. Profile of a line tolerance differs from profile of a surface tolerance in that it:

    Answer: Controls only a single cross-sectional slice at each measuring location

    Profile of a line controls the profile at individual cross-sections independently, whereas profile of a surface controls the entire surface as one zone.

  7. Which surface finish lay symbol indicates that the predominant surface marks are circular relative to the center of the surface?

    Answer: C (circular lay)

    The lay symbol 'C' designates a circular lay pattern, which is typical of surfaces produced by facing operations on a lathe.