Sewing Machine Operation and Maintenance
Questions here cover the named parts of the machine and their functions, the correct threading order, tension faults, and the routine care that keeps the machine working.
Parts and their functions
- Spool pin holds the reel; the tension discs grip the upper thread; the take-up lever feeds it to the needle.
- Needle bar and clamp hold the needle; presser foot holds the fabric; feed dog moves it forward.
- Needle plate covers the bobbin area; bobbin case holds the lower thread; balance or hand wheel turns the mechanism.
Threading and stitching
- Thread with the presser foot UP so the thread seats between the tension discs.
- Wind the bobbin with the clutch released; thread the bobbin case in the direction marked on the case.
- Stitch length: about 2.5 mm for medium cotton, 3–4 mm for basting, 1.5 mm for fine fabric.
- Always test on a scrap of the same fabric before stitching the garment.
Maintenance
- Brush lint from the feed dog and bobbin case after every use.
- Oil only the points marked in the manual, one or two drops of machine oil.
- Never pull the fabric through; let the feed dog move it.
- Cover the machine and keep it dry.
Worked example
Loops and tangles appear on the underside of the fabric. Reasoning: the upper thread is reaching the underside before it interlaces, so the upper tension is too loose or the machine is wrongly threaded. The student re-threads with the presser foot up, then tightens the upper tension one number at a time and tests again. Loops on the top surface would instead point to the bobbin - unevenly wound or too loose.
Traps that cost marks
- Threading with the presser foot down, so the thread never enters the tension discs.
- Running the machine with the presser foot down and no fabric, rubbing the feed dog against the needle plate.
- Using a bent or blunt needle and blaming the tension.
- Forgetting to oil and clean, so the machine stiffens.