South Carolina Industrial Sewing
Machine Technician Certification
License Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
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1. Which of the following needles is most appropriate for sewing
heavy-weight canvas on an industrial walking foot machine?
A. 9/65
B. 11/75
C. 16/100
D. 18/110
The 16/100 needle size is designed for heavy-weight materials like
canvas and provides sufficient strength without frequent breakage.
2. What is the primary function of the feed dog on an industrial sewing
machine?
A. Control thread tension
B. Move fabric through the machine
C. Hold the needle in place
D. Trim excess fabric
Feed dogs grip and advance the material under the presser foot,
ensuring consistent stitch length.
,3. When performing routine maintenance, which lubricant should be
used on a typical industrial sewing machine’s moving parts?
A. Water
B. Household oil
C. Industrial sewing machine oil
D. Grease only
Industrial sewing machine oil is formulated to provide proper
lubrication without gumming up the mechanisms.
4. What does a skipped stitch generally indicate during sewing
operations?
A. Thread tension too tight
B. Bobbin case improperly wound
C. Incorrect needle size or bent needle
D. Feed dog set too high
Skipped stitches commonly result from needle issues such as the
wrong size or a bent needle that fails to penetrate properly.
5. Which type of stitch is most suitable for garment seams requiring
flexibility and strength?
A. Straight stitch only
B. Lockstitch
C. Basting stitch
D. Chain stitch
Lockstitch provides a balanced, strong stitch appropriate for garment
seams while maintaining flexibility.
6. A bobbin that consistently jams suggests what primary issue?
A. Needle size too large
B. Presser foot pressure too low
C. Incorrect bobbin installation or tension
D. Incorrect feed dog timing
, Improper bobbin placement or incorrect tension can cause thread
jams and inconsistent stitch formation.
7. What is the correct action when the industrial machine produces
excessive lint buildup?
A. Increase needle size
B. Clean machine components and lint traps
C. Tighten the needle clamp
D. Replace the presser foot
Regular cleaning of lint buildup prevents mechanical issues and
maintains stitch quality.
8. Which part of the sewing machine controls the upper thread
tension?
A. Feed dog
B. Needle bar
C. Tension discs
D. Bobbin case
Tension discs regulate the tension applied to the upper thread,
critical for balanced stitches.
9. What is the primary cause of thread breakage on the top thread?
A. Bobbin wound too loosely
B. Feed dog height too low
C. Tension too tight or damaged needle
D. Wrong presser foot
Excessive tension or a damaged needle often causes top thread
breakage.
10. For sewing heavy leather, which presser foot is most
appropriate?
A. Standard zigzag foot
B. Buttonhole foot
Machine Technician Certification
License Exam Practice Questions And
Correct Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant Download
1. Which of the following needles is most appropriate for sewing
heavy-weight canvas on an industrial walking foot machine?
A. 9/65
B. 11/75
C. 16/100
D. 18/110
The 16/100 needle size is designed for heavy-weight materials like
canvas and provides sufficient strength without frequent breakage.
2. What is the primary function of the feed dog on an industrial sewing
machine?
A. Control thread tension
B. Move fabric through the machine
C. Hold the needle in place
D. Trim excess fabric
Feed dogs grip and advance the material under the presser foot,
ensuring consistent stitch length.
,3. When performing routine maintenance, which lubricant should be
used on a typical industrial sewing machine’s moving parts?
A. Water
B. Household oil
C. Industrial sewing machine oil
D. Grease only
Industrial sewing machine oil is formulated to provide proper
lubrication without gumming up the mechanisms.
4. What does a skipped stitch generally indicate during sewing
operations?
A. Thread tension too tight
B. Bobbin case improperly wound
C. Incorrect needle size or bent needle
D. Feed dog set too high
Skipped stitches commonly result from needle issues such as the
wrong size or a bent needle that fails to penetrate properly.
5. Which type of stitch is most suitable for garment seams requiring
flexibility and strength?
A. Straight stitch only
B. Lockstitch
C. Basting stitch
D. Chain stitch
Lockstitch provides a balanced, strong stitch appropriate for garment
seams while maintaining flexibility.
6. A bobbin that consistently jams suggests what primary issue?
A. Needle size too large
B. Presser foot pressure too low
C. Incorrect bobbin installation or tension
D. Incorrect feed dog timing
, Improper bobbin placement or incorrect tension can cause thread
jams and inconsistent stitch formation.
7. What is the correct action when the industrial machine produces
excessive lint buildup?
A. Increase needle size
B. Clean machine components and lint traps
C. Tighten the needle clamp
D. Replace the presser foot
Regular cleaning of lint buildup prevents mechanical issues and
maintains stitch quality.
8. Which part of the sewing machine controls the upper thread
tension?
A. Feed dog
B. Needle bar
C. Tension discs
D. Bobbin case
Tension discs regulate the tension applied to the upper thread,
critical for balanced stitches.
9. What is the primary cause of thread breakage on the top thread?
A. Bobbin wound too loosely
B. Feed dog height too low
C. Tension too tight or damaged needle
D. Wrong presser foot
Excessive tension or a damaged needle often causes top thread
breakage.
10. For sewing heavy leather, which presser foot is most
appropriate?
A. Standard zigzag foot
B. Buttonhole foot
