What is spirality?#
Spirality is the twisting of weft-knitted fabric, where the wales slant at an angle instead of running straight along the length. In garments, it shows as side seams that move towards the front or back after washing, hems that do not hang level and prints that look skewed.
It is most common in single jersey and other single knits. See spirality in knitted fabric for the background.
What it looks like#
- Side seams of T-shirts swinging towards the front on one side and the back on the other.
- A diagonal line of wales visible when you look closely at the fabric.
- Hems that are uneven after washing.
- Stripes and prints that look tilted.
Where it occurs#
- Single jersey T-shirts, especially lightweight and 100% cotton.
- Tubular garments without side seams, where the whole body rotates.
- Fabric with single yarns of high twist.
Likely causes#
The main driver is the torque in the yarn: single yarns with high twist try to untwist, and in a single knit fabric, this tilts the loops. Knitting on machines with many feeders adds a small course inclination. Finishing can hide the twist temporarily; washing releases it.
Machine-related causes#
- Multi-feeder circular machines produce courses as a spiral, which adds inclination.
- Finishing machinery: tubular compactors and dryers that do not straighten the fabric leave the twist in place.
- Stenter straighteners not set or not used for open-width fabric.
Material-related causes#
- Yarn twist: higher twist factors and twist liveliness increase spirality.
- Yarn type: open-end and ring yarns behave differently; plied yarns are more balanced.
- Loose fabric: longer stitch lengths let loops tilt more.
Operator and process-related causes#
- Cutting along the fabric edge or tube fold instead of along the wale, when the fabric is already twisted.
- Marking panels without checking the wale direction.
Method-related causes#
- Finishing route: tubular finishing cannot straighten twisted courses as well as open-width finishing with a straightener.
- Testing: no spirality test on washed bulk fabric before cutting.
How to confirm the cause#
- Measure spirality on washed fabric samples and garments with the buyer's method. See dimensional stability testing.
- Check the wale angle on unwashed cut panels. If panels were cut off-grain, the garment twists even if the fabric itself is acceptable.
- Compare yarn lots and twist: a new yarn lot often explains a sudden change.
- Check stitch length against the quality standard.
- Review finishing records for the lot.
Immediate containment#
- Stop cutting the affected fabric lot and test washed samples.
- Wash test garments already sewn and compare with the buyer's limit.
- Where the fabric is twisted but within limit, cut panels along the wale line.
- Hold finished goods from the lot until results are confirmed.
Corrective action#
| Cause | Corrective action |
|---|---|
| Yarn twist | Change yarn specification: lower twist, plied or compact yarn |
| Loose fabric | Tighten stitch length for the count |
| Finishing | Open-width finishing with straightening; correct overfeed |
| Off-grain cutting | Mark and cut along the wale; check at cutting |
| Untested bulk | Test each lot before cutting |
Preventive action#
- Spirality limits in the fabric specification, with the test method.
- Yarn approval including twist, for single jersey programs.
- Bulk testing of every lot after washing.
- Cutting instructions to align patterns to the wale when needed.
Inspection notes#
- Measure garments after the buyer's specified wash, laid flat.
- Record spirality by fabric lot and garment size.
- Twist beyond the buyer's limit is usually a major defect.
Example investigation#
A basic cotton T-shirt fails a buyer test with side seam twist well above the limit. The fabric lot's own wash test shows moderate spirality, within the limit. Checking cut panels in stock shows the front and back panels were cut with the pattern aligned to the tube fold, while the wales on that lot run at a noticeable angle to the fold. The garment twist is the fabric spirality plus the off-grain cutting.
Actions: remaining panels were checked and recut where possible, markers were redrawn with a wale line reference, and the fabric supplier was asked to improve straightening for the next lots. Spirality testing of garments was added to the first bulk check.
Factory checklist#
- Spirality limit and method in the fabric specification
- Yarn twist and type approved
- Stitch length checked
- Fabric finished with straightening where needed
- Bulk spirality tested after washing before cutting
- Panels cut on the wale line
Related guides: skewing, excessive shrinkage.