The needle is a small part with a large effect on seam quality. The wrong needle can cut yarns in knitted fabric, cause skipped stitches, break thread and damage delicate fabrics. Choosing a needle means getting three things right: the system, the size and the point.
Needle system#
The needle system defines the needle's dimensions (shank, length, eye position, scarf) to fit a machine type. Lockstitch, overlock, coverstitch and chainstitch machines use different systems. Always use the system specified in the machine manual. A needle from the wrong system may fit in the clamp but will not form stitches correctly.
Needle size#
Industrial needles are sized by the blade diameter.
- Metric size (Nm): blade diameter in hundredths of a millimeter. Nm 80 = 0.80 mm.
- Singer size: an older numbering system, still printed with the metric size on most packs.
| Metric (Nm) | Singer | Typical use |
|---|---|---|
| 60 | 8 | Very fine fabrics, lingerie |
| 65 | 9 | Fine knits and wovens |
| 70 | 10 | Light T-shirt jersey, shirting |
| 75 | 11 | T-shirts, light knits, shirts |
| 80 | 12 | General knits and light wovens |
| 90 | 14 | Medium wovens, twill, fleece |
| 100 | 16 | Heavier wovens, denim seams |
| 110 | 18 | Heavy denim, canvas |
| 120 to 140 | 19 to 22 | Very heavy fabrics, bags, belts |
These ranges are starting points. The fabric and thread decide the final choice.
Matching needle and thread#
The thread must pass freely through the needle eye and lie in the long groove of the needle as it penetrates the fabric. If the thread is too thick for the needle:
- The thread is abraded and breaks.
- Loop formation is poor, causing skipped stitches.
If the needle is too thick for the thread:
- Holes are bigger than needed, and seams look open.
- Fabric damage increases.
Thread manufacturers publish recommended needle sizes for each thread ticket. Use those tables as the first reference.
Point types#
| Point | Shape | Use |
|---|---|---|
| Set point (regular, R) | Slightly rounded sharp point | Woven fabrics |
| Light ball point (SES) | Small rounded point | Fine knits, delicate wovens |
| Medium ball point (SUK) | Larger rounded point | Coarser knits, elastic fabrics |
| Heavy ball point (SKF) | Very rounded | Coarse knits, elastic tapes, elastane-rich fabrics |
| Cutting points | Blade-shaped | Leather and non-woven materials only |
Point designation letters vary slightly between needle makers; check the maker's chart.
Ball points push yarns aside instead of piercing them. That prevents yarn breaks in knits, which would otherwise start holes and runs. See needle cut.
Special needles#
- Anti-skip needles with a modified scarf, for elastic and synthetic fabrics that tend to cause skipped stitches.
- Coated needles (for example titanium or chrome variants) to reduce wear and heat on dense or synthetic fabrics.
- Needles with reinforced blades to reduce deflection on thick seams.
Needle heat#
At high speed, friction heats the needle. On synthetic fabrics and threads, this can melt fibers or thread, causing thread breakage and damaged holes. Reduce speed, use coated needles, or use needle coolers where needed.
Needle changing and control#
- Change needles on a schedule, and immediately when bent, blunt or damaged.
- Run a broken needle policy: all fragments of a broken needle must be found and recorded before work continues. Missing fragments are a serious safety risk in garments. See needle breakage.
- Keep needle stock in a controlled box with issue and return records.
Checklist#
- Needle system matches the machine
- Size suits both the thread and the fabric
- Point type suits the fabric (ball point for knits)
- Needle changed at style change and on schedule
- Broken needle control in place
Related guides#
- Sewing thread selection: matching thread size to the needle.
- Stitch types: which stitch types and machines need which needle systems.
- Sewing machine types: the machine types the needles are fitted to.
- Thread breakage: how the wrong needle causes thread breaks.
- Different types of knit fabrics: the knit fabrics that need ball point needles.