Manufacturer · Fashion & Home Accessories
For overlocking, ticket 120 polyester thread on cones is used most often: spun polyester for the needles and spun or textured polyester for the loopers. Textured thread is soft, covers the edge densely and stretches together with the jersey. Since an overlocker works with 3, 4 or 5 threads at once, overlock threads are bought on large cones in matching colours.
How thread works in an overlocker
The overlocker (serger, overlock machine) trims the edge of the fabric and covers it with loops. The needle threads form the seam, and the looper threads wrap the edge. The loopers carry less tension but use much more thread – on a 4-thread overlock, the loopers account for over two thirds of the total consumption. That is why a thread that covers well and is economical is sought for them.
Types of overlock thread
Spun polyester
The universal option. It is used in the needles and in the loopers on woven fabrics. It is strong, with a smooth surface and good behaviour at high speed. Standard weights are ticket 120 and 100.
Textured polyester (woolly, bulked)
Textured thread has bulky, fluffed-up filaments. It spreads in the seam, covers the edge densely and is soft to the touch – ideal for lingerie, swimwear, sportswear and children's clothing, where the seam touches the skin. Its elasticity helps the seam not to break when the jersey is stretched. It is used mainly in the loopers, and sometimes in the needle for coverstitch.
Textured polyamide
Softer and more elastic than polyester, preferred for swimwear and lingerie. It is more sensitive to high ironing temperatures, so be careful with the iron.
Core-spun
For heavy fabrics and workwear, core-spun thread is used in the needles of the overlock and the 5-thread seam for extra strength.
Overlock threads by fabric
| Fabric | Needles | Loopers |
|---|---|---|
| Poplin, cotton, dress wovens | spun polyester ticket 120 | spun polyester ticket 120 |
| Single jersey, T-shirts | spun polyester ticket 120 | textured or spun polyester |
| Lingerie, swimwear, Lycra | spun polyester ticket 120–150 | textured polyamide or polyester |
| Sweatshirt, heavy jersey | spun polyester ticket 100–120 | textured polyester |
| Denim, workwear | core-spun ticket 100–80 | spun polyester ticket 100 |
How many cones you need
- 3-thread overlock – 3 cones (1 needle, 2 loopers); for edge finishing on light fabrics.
- 4-thread overlock – 4 cones (2 needles, 2 loopers); the most widely used, for sewing and finishing jersey at the same time.
- 5-thread (safety stitch) – 5 cones; chainstitch plus 3-thread overlock, for wovens and workwear.
- coverstitch – 2–3 needles and 1 looper; for jersey hems.
When planning an order, count cones by number of machines and colours, not just by number of items. One colour running on several machines requires correspondingly more cones.
Setting the tension
Good edge coverage depends more on tension than on the thread itself:
- Start with the machine's standard settings.
- If the upper looper loops are pulled under the fabric – tighten the upper looper or loosen the lower one.
- If the edge puckers – reduce the looper tension and check the differential feed.
- On jersey, increase the differential feed so that the edge does not stretch into waves.
- With textured thread, reduce the looper tension – it needs freedom to spread.
Tip: when setting up, use four different thread colours. That way you can see immediately which thread has the wrong tension.
Overlock thread colour
Inside seams are rarely visible, so many factories work with a limited set of core colours – white, black, navy, grey, beige. For sheer fabrics, reversible styles and items with visible seams, the colour must match the fabric. You will find more tips on choosing colours in the sewing threads catalogue.
Common problems
- The needle thread breaks – too much tension, a blunt needle or the thread is caught on the stand.
- Skipped stitches – an unsuitable needle for jersey or a wrongly inserted needle.
- Lint around the loopers – low-grade spun thread; clean the machine every day.
- A stiff, scratchy seam – switch the looper thread to textured thread.
On jersey that also needs elastic along the edge, the overlocker often attaches the elastic while finishing the seam – in that case textured thread in the loopers gives the softest result.
Overlocker maintenance
An overlocker trims the fabric and generates a lot of lint, especially with spun and cotton threads. Clean the area around the knives and loopers daily with a brush, without blowing the lint further into the machine. Oil according to the manufacturer's instructions and change needles regularly – on an overlocker, a blunt needle quickly leads to skipped stitches on jersey. Also check the knives: a worn knife tears the edge and the thread cannot cover it evenly.
Storing cones
Textured thread is more sensitive to dust and direct light, because its bulky structure traps dirt. Keep cones in closed boxes or on shelves away from windows and heaters. Do not leave cones on the machine for weeks without use – the thread on the surface fades and gets dusty, and this shows in the seam.
Overlock threads from Polkom
Polkom manufactures and delivers sewing and overlock threads on cones to garment factories and ateliers across Europe. In the threads category you will find the main groups and colours. Send us the type of fabrics and machines via the contact page – we will suggest overlock threads and samples.
