Ohio CNC Operator Level 2 Practice
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales
2025|2026 Q&A | Instant Download Pdf
1. What does G00 code typically command on a CNC machine?
A) Feed at programmed feed rate
B) Rapid positioning
C) Circular interpolation
D) Thread cutting
Rationale: G00 is used for rapid, non-cutting moves to position the
tool quickly.
2. Which coordinate system is referenced to the machine’s physical zero
point?
A) Work offset
B) Tool offset
C) Machine coordinate system (MCS)
D) Local coordinate system
, Rationale: MCS is fixed to the machine and used as a reference for all
positions.
3. What is the primary function of G01 code?
A) Rapid traverse
B) Drill cycle
C) Linear interpolation at a programmed feed rate
D) Peck drilling
Rationale: G01 moves the tool in a straight line at a controlled feed
rate for cutting.
4. Which coolant type is typically used for aluminum machining?
A) Water-soluble oil
B) Straight oil
C) Synthetic oil
D) Water-based coolant
Rationale: Water-based coolant provides good cooling and chip
evacuation for aluminum.
5. What does the “tool offset” compensate for?
A) Material hardness
B) Tool length and diameter variations
C) Machine vibration
D) Workholding misalignment
Rationale: Tool offsets ensure the machine compensates for actual
tool size and length.
,6. Which factor has the greatest effect on tool life?
A) Machine weight
B) Cutting speed
C) Workpiece color
D) Coolant color
Rationale: Cutting speed directly affects heat generation and tool
wear.
7. What does the G02 command perform?
A) Linear movement
B) Clockwise circular interpolation
C) Counterclockwise circular interpolation
D) Drill cycle
Rationale: G02 moves the tool along a clockwise arc in the XY plane.
8. Which type of CNC machine is primarily used for turning?
A) Milling machine
B) Drilling machine
C) Lathe
D) EDM machine
Rationale: A lathe rotates the workpiece and uses a stationary
cutting tool for turning operations.
9. When programming a part in inches, what code is used?
A) G21
B) G20
, C) G90
D) G91
Rationale: G20 sets the CNC to inch mode; G21 sets metric mode.
10. What does the “fixture offset” compensate for?
A) Tool wear
B) Machine calibration
C) Workpiece location on the table
D) Coolant flow
Rationale: Fixture offsets adjust the coordinate system to match the
physical placement of the workpiece.
11. What is the purpose of peck drilling cycles?
A) Increase spindle speed
B) Break chips and reduce heat during deep hole drilling
C) Decrease tool diameter
D) Polish the hole surface
Rationale: Peck drilling retracts the drill periodically to prevent chip
clogging and overheating.
12. Which motion mode is G03 used for?
A) Rapid traverse
B) Linear feed
C) Counterclockwise circular interpolation
D) Drilling cycle
Rationale: G03 performs CCW arcs in the XY plane.
Exam Questions And Correct Answers
(Verified Answers) Plus Rationales
2025|2026 Q&A | Instant Download Pdf
1. What does G00 code typically command on a CNC machine?
A) Feed at programmed feed rate
B) Rapid positioning
C) Circular interpolation
D) Thread cutting
Rationale: G00 is used for rapid, non-cutting moves to position the
tool quickly.
2. Which coordinate system is referenced to the machine’s physical zero
point?
A) Work offset
B) Tool offset
C) Machine coordinate system (MCS)
D) Local coordinate system
, Rationale: MCS is fixed to the machine and used as a reference for all
positions.
3. What is the primary function of G01 code?
A) Rapid traverse
B) Drill cycle
C) Linear interpolation at a programmed feed rate
D) Peck drilling
Rationale: G01 moves the tool in a straight line at a controlled feed
rate for cutting.
4. Which coolant type is typically used for aluminum machining?
A) Water-soluble oil
B) Straight oil
C) Synthetic oil
D) Water-based coolant
Rationale: Water-based coolant provides good cooling and chip
evacuation for aluminum.
5. What does the “tool offset” compensate for?
A) Material hardness
B) Tool length and diameter variations
C) Machine vibration
D) Workholding misalignment
Rationale: Tool offsets ensure the machine compensates for actual
tool size and length.
,6. Which factor has the greatest effect on tool life?
A) Machine weight
B) Cutting speed
C) Workpiece color
D) Coolant color
Rationale: Cutting speed directly affects heat generation and tool
wear.
7. What does the G02 command perform?
A) Linear movement
B) Clockwise circular interpolation
C) Counterclockwise circular interpolation
D) Drill cycle
Rationale: G02 moves the tool along a clockwise arc in the XY plane.
8. Which type of CNC machine is primarily used for turning?
A) Milling machine
B) Drilling machine
C) Lathe
D) EDM machine
Rationale: A lathe rotates the workpiece and uses a stationary
cutting tool for turning operations.
9. When programming a part in inches, what code is used?
A) G21
B) G20
, C) G90
D) G91
Rationale: G20 sets the CNC to inch mode; G21 sets metric mode.
10. What does the “fixture offset” compensate for?
A) Tool wear
B) Machine calibration
C) Workpiece location on the table
D) Coolant flow
Rationale: Fixture offsets adjust the coordinate system to match the
physical placement of the workpiece.
11. What is the purpose of peck drilling cycles?
A) Increase spindle speed
B) Break chips and reduce heat during deep hole drilling
C) Decrease tool diameter
D) Polish the hole surface
Rationale: Peck drilling retracts the drill periodically to prevent chip
clogging and overheating.
12. Which motion mode is G03 used for?
A) Rapid traverse
B) Linear feed
C) Counterclockwise circular interpolation
D) Drilling cycle
Rationale: G03 performs CCW arcs in the XY plane.
