Cutting, Stitching and Construction Techniques
This domain covers layout and cutting, machine operation, seam choice and the order of construction. Questions often ask which seam suits a fabric, why stitches loop, or what step comes next in assembling a garment.
Layout and cutting
Check fabric for defects and shrinkage first. Lay all pieces in one direction if the fabric has nap, shine or a one-way print. Match plaids at the seam line, not the cutting line. Place grainline arrows parallel to the selvedge, cut notches outward, and transfer markings with tailor's chalk or thread tacks. Use sharp shears and do not lift the fabric while cutting.
Machine and stitch basics
Match needle size to fabric: fine needle for voile, medium for cotton, heavier for denim. Stitch length is about 2 to 2.5 mm for medium fabric, 1.5 to 2 mm for fine fabric, and 3 to 3.5 mm for basting. Balanced tension gives stitches level on both sides.
Seams and finishes
- Plain seam with zigzag or pinking for firm fabrics.
- French seam for sheer and lightweight fabrics.
- Flat fell or run-and-fell for denim and shirts.
- Bound seam for unlined jackets.
Worked example
A French seam uses 1.5 cm total allowance. Stitch wrong sides together at 0.75 cm, trim to 0.3 cm, turn right sides out, then stitch 0.6 cm. Reasoning: the second row of stitching encloses the first raw edge, so no raw edges show and the seam is strong enough for sheer fabric.
Traps
Loops under the fabric usually mean thread tension or bobbin winding is wrong, not a dull needle. Do not cut a fold line open. Skipping staystitching lets necklines stretch.
Key points
- Lay nap and one-way prints in one direction; match plaids at the seam line.
- French seams suit sheer fabric; flat fell suits denim.
- Stitch length 2 to 2.5 mm for medium fabric; 3 to 3.5 mm for basting.
- Loops underneath indicate tension or bobbin problems.