Sewing Machines, Tools and Equipment
This domain covers the domestic and industrial sewing machine, essential tools, stitch formation, basic adjustments and safe maintenance.
Core concepts
- Main parts include the needle, needle plate, presser foot, feed dog, bobbin, bobbin case, take-up lever, tension discs and handwheel.
- Stitch length is controlled by the feed regulator; longer stitches are for basting, shorter stitches for fine seams. Tension balances upper and lower threads.
- Needle size and type must match fabric: fine needles for lightweight cloth, stronger needles for denim, ballpoint needles for knits.
- Tools include measuring tape, scissors, seam ripper, pins, tailor’s chalk, French curve, set square and tracing wheel. Keep them clean and sharp.
Worked example
A machine forms loops under the fabric and occasionally skips stitches. Reason through the checks: rethread the upper path, check the bobbin for correct winding and seating, replace a blunt or wrong needle, clean lint from the feed dog and bobbin area, then test tension on a scrap. Only adjust tension after confirming threading and needle condition, because incorrect threading can imitate a tension fault.
Traps that cost marks
Do not tighten the upper tension immediately when the bobbin thread loops; diagnose threading and bobbin first. Do not use a heavy needle on fine fabric. Do not pull fabric through the machine; let the feed dog move it. Do not remove the needle guard or safety devices.
Exam focus
Labelled-part questions, fault diagnosis, needle selection and tool identification.