Tennessee Precision
Machining Certification Exam:
CNC Lathe II Exam Questions
And Correct Answers (Verified
Answers) Plus Rationales
2025/2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of rough turning on a CNC
lathe?
A. Improve surface finish
B. Remove maximum material efficiently
C. Achieve final dimensions
D. Reduce tool wear
Answer: B
Rationale: Rough turning is used to remove large amounts
of material quickly before finishing operations.
2. Which tool is most commonly used for internal machining
operations?
,A. Parting tool
B. Boring bar
C. Facing tool
D. Threading tool
Answer: B
Rationale: A boring bar is designed for enlarging and
finishing internal diameters.
3. What does G96 control in CNC lathe programming?
A. Constant spindle speed
B. Constant surface speed
C. Tool offset
D. Feed rate mode
Answer: B
Rationale: G96 maintains constant surface speed as
diameter changes.
4. What is the function of a work offset (G54)?
A. Sets tool length
B. Defines machine limits
C. Establishes part zero reference
D. Controls spindle direction
Answer: C
Rationale: Work offsets define the coordinate system origin
for machining.
,5. Which operation is typically performed first on a raw bar
stock?
A. Threading
B. Grooving
C. Facing
D. Parting
Answer: C
Rationale: Facing creates a flat reference surface for further
operations.
6. What does G97 command do?
A. Activates constant surface speed
B. Cancels constant surface speed
C. Sets tool length compensation
D. Controls coolant
Answer: B
Rationale: G97 switches spindle to fixed RPM mode.
7. What is the purpose of a chamfer?
A. Increase diameter
B. Remove sharp edges
C. Improve tool life
D. Increase feed rate
Answer: B
Rationale: Chamfers eliminate sharp edges for safety and
assembly ease.
, 8. Which tool is best for cutting external threads?
A. Boring bar
B. Parting tool
C. Threading insert
D. Facing tool
Answer: C
Rationale: Threading inserts are designed to cut precise
threads.
9. What is G00 used for?
A. Cutting feed move
B. Rapid positioning
C. Threading cycle
D. Drilling cycle
Answer: B
Rationale: G00 moves the tool quickly between positions
without cutting.
10. What is the main risk of excessive feed rate?
A. Better finish
B. Tool breakage
C. Increased accuracy
D. Lower spindle speed
Machining Certification Exam:
CNC Lathe II Exam Questions
And Correct Answers (Verified
Answers) Plus Rationales
2025/2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of rough turning on a CNC
lathe?
A. Improve surface finish
B. Remove maximum material efficiently
C. Achieve final dimensions
D. Reduce tool wear
Answer: B
Rationale: Rough turning is used to remove large amounts
of material quickly before finishing operations.
2. Which tool is most commonly used for internal machining
operations?
,A. Parting tool
B. Boring bar
C. Facing tool
D. Threading tool
Answer: B
Rationale: A boring bar is designed for enlarging and
finishing internal diameters.
3. What does G96 control in CNC lathe programming?
A. Constant spindle speed
B. Constant surface speed
C. Tool offset
D. Feed rate mode
Answer: B
Rationale: G96 maintains constant surface speed as
diameter changes.
4. What is the function of a work offset (G54)?
A. Sets tool length
B. Defines machine limits
C. Establishes part zero reference
D. Controls spindle direction
Answer: C
Rationale: Work offsets define the coordinate system origin
for machining.
,5. Which operation is typically performed first on a raw bar
stock?
A. Threading
B. Grooving
C. Facing
D. Parting
Answer: C
Rationale: Facing creates a flat reference surface for further
operations.
6. What does G97 command do?
A. Activates constant surface speed
B. Cancels constant surface speed
C. Sets tool length compensation
D. Controls coolant
Answer: B
Rationale: G97 switches spindle to fixed RPM mode.
7. What is the purpose of a chamfer?
A. Increase diameter
B. Remove sharp edges
C. Improve tool life
D. Increase feed rate
Answer: B
Rationale: Chamfers eliminate sharp edges for safety and
assembly ease.
, 8. Which tool is best for cutting external threads?
A. Boring bar
B. Parting tool
C. Threading insert
D. Facing tool
Answer: C
Rationale: Threading inserts are designed to cut precise
threads.
9. What is G00 used for?
A. Cutting feed move
B. Rapid positioning
C. Threading cycle
D. Drilling cycle
Answer: B
Rationale: G00 moves the tool quickly between positions
without cutting.
10. What is the main risk of excessive feed rate?
A. Better finish
B. Tool breakage
C. Increased accuracy
D. Lower spindle speed
