Practice Test Geeks(CNC) Computer Numerical Control Machinist Technical Practice Test
← All CNC Flashcard Decks

Precision Measurement & Quality Control Flashcards

7 cards from real CNC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Precision Measurement & Quality Control flashcards as text

  1. A machinist performing a first article inspection (FAI) finds one dimension is 0.001" outside the bilateral tolerance. The correct first action is:

    Answer: Document the nonconformance and initiate a Material Review Board (MRB) process

    A nonconforming part must be documented and submitted to MRB (or equivalent disposition authority) — it cannot be passed, scrapped, or ignored without formal review.

  2. On a feature control frame reading ⌀0.005 M A B, what does the symbol M indicate?

    Answer: Bonus tolerance is allowed as the feature departs from Maximum Material Condition

    The MMC modifier (M) means bonus tolerance equal to the departure from MMC is added to the stated tolerance as the feature's actual size moves away from MMC.

  3. A bore gauge is zeroed on a 2.000" master ring gauge and then inserted into a bored hole, reading +0.0008". The actual hole diameter is:

    Answer: 2.0008"

    A positive reading means the hole is larger than the master; 2.000" + 0.0008" = 2.0008".

  4. Which chart type is most appropriate for tracking the variation (spread) within subgroups on a CNC turning process?

    Answer: R-chart (Range chart)

    The R-chart (Range chart) monitors the within-subgroup variation (spread) by tracking the difference between the highest and lowest values in each sample.

  5. A CNC machinist uses a go/no-go plug gauge on a drilled hole. The 'go' gauge enters but the 'no-go' gauge also enters. This means the hole is:

    Answer: Oversized — beyond the maximum material condition

    If the no-go gauge enters, the hole is larger than the maximum allowable size (LMC for a hole), making the part nonconforming oversize.

  6. When a CNC part drawing calls out a flatness tolerance of 0.002", the measurement is made by:

    Answer: Measuring the distance between the highest and lowest surface points with a CMM or dial indicator sweep

    Flatness is measured by sweeping the surface and recording the total range (highest to lowest point), which must be within the stated tolerance zone.

  7. ISO gauge block grades are ranked in order of precision as:

    Answer: Grade K (most precise) → Grade 0 → Grade 1 → Grade 2 (least)

    ISO 3650 defines gauge block accuracy grades as K (calibration/master), 0, 1, and 2, with K being the highest precision.