Yarn twist and its types
Twist is the spiral turning of fibres round the yarn, counted as turns per inch or metre. Its direction is S or Z; its amount sets strength, feel and look.
S twist and Z twist
Direction does not change strength; it matters for plying, for crepe effects (alternating S and Z yarns) and for how twill lines show.
Amount of twist
| Amount | Effect on yarn | Used for |
|---|---|---|
| Low (soft) twist | Soft, bulky, lustrous if filament; weaker, more absorbent, pills more | Weft yarns, napped fabrics, knitting wool, terry loops |
| Medium (average) twist | Balance of strength, softness and smoothness | Most weaving yarns |
| High (hard) twist | Firm, smooth, strong, less lustrous and less absorbent; crisp | Warp yarns, voile, gabardine |
| Crepe twist | Very high twist; yarn kinks and shrinks, giving a pebbly surface | Georgette, crepe, chiffon (alternate S and Z yarns) |
Why twist matters
- Strength: more twist grips staple fibres tighter and raises strength up to an optimum; beyond it, fibres are strained and strength falls.
- Lustre: low-twist filament yarns shine; high twist breaks up the reflecting surface.
- Hand and warmth: soft twist feels fluffy and warm; hard twist feels crisp and cool.
- Absorbency: loose twist lets water in quickly (towels); tight twist resists it.
- Pilling and wear: high twist holds fibre ends in, so the fabric pills less.
- Kinking: highly twisted yarns try to untwist, which gives crepe effects but can also twist garments out of shape.
Working out twist
On a twist tester, a 25 cm length of yarn untwists completely after 120 turns. Find its twist in turns per metre and turns per inch (1 m = 39.37 inches).
- Length = 25 cm = 0.25 m.
- TPM = turns ÷ length in metres = 120 ÷ 0.25 = 480 turns per metre.
- TPI = TPM ÷ 39.37 = 480 ÷ 39.37 = 12.19…, which rounds to 12.2 turns per inch (one decimal place).
- Check: 12.19 × 39.37 = 479.9, close to 480.
480 turns per metre, or about 12.2 turns per inch.
Soft-twist cotton terry absorbs fast, so it suits kitchen and bath towels. Crepe and georgette saris (very high twist) can shrink sharply in hot water, so wash them cool and dry them flat.
2 marks: “What is S and Z twist?” Twist directions seen with the yarn upright: S spirals slope like the middle of S (upper left to lower right); Z spirals slope like the middle of Z (upper right to lower left).
5 marks: “Explain the effect of twist on yarn and fabric properties.” Define twist and TPI; amounts (soft, medium, hard, crepe); effects on strength (optimum), lustre, hand, absorbency, pilling, kinking; examples.
Look at the middle stroke: S leans top-left to bottom-right, Z leans top-right to bottom-left. Soft twist gives soft cloth; crepe twist gives crinkled cloth.