Practice Test Geeks(CNC) Computer Numerical Control Machinist Technical Practice Test
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G-Code & M-Code Programming 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 G-Code & M-Code Programming flashcards as text

  1. What G-code is used to set the tool length offset?

    Answer: G43

    G43 applies a positive tool length offset from the H-word register to compensate for tool length differences.

  2. In a CNC program block 'G02 X2.0 Y0.0 I1.0 J0.0', what do I and J represent?

    Answer: Arc center offsets from the start point

    I and J define the distance and direction from the arc start point to the arc center in the X and Y axes respectively.

  3. Which M-code activates flood coolant?

    Answer: M08

    M08 turns on flood coolant, which delivers a high volume of liquid coolant to the cutting zone.

  4. What is a 'canned cycle' in CNC programming?

    Answer: A pre-programmed multi-step operation called with a single G-code

    Canned cycles (G73–G89) are built-in multi-step routines like drilling, tapping, and boring activated by a single G-code block.

  5. What does a negative I or J value indicate in arc programming?

    Answer: The arc center is in the negative direction from the start point

    Negative I or J values mean the arc center is located in the negative X or Y direction relative to the arc's starting point.

  6. Which G-code cancels tool length compensation?

    Answer: G49

    G49 cancels any active tool length offset, returning the tool to its programmed position without compensation.

  7. In CNC turning, what does 'G71' typically command?

    Answer: Rough turning cycle

    G71 is a stock removal (rough turning) canned cycle that removes material in multiple passes along a defined contour.