Overlocker Tension Guide - How to Identify and Fix ProblemsUpdated 2 days ago
Overlocker Tension Guide - How to Identify and Fix Problems
Getting the tension right on an overlocker can feel like a dark art, but once you know what each thread does and what to look for, it becomes much more straightforward. Before adjusting anything, make sure the machine is threaded correctly - see our How to Re-thread an Overlocker guide first if you're not sure.
Understanding your tension dials
Most overlockers have four tension dials - one for each thread. Each dial controls how tightly that thread feeds through the machine as you sew.
- Increasing the number on a dial tightens that thread's tension - decreasing it loosens it
- Always make small adjustments one dial at a time and test on scrap fabric after each change
- Default values are usually marked on the machine - check your manual for your model's default markings and start from there if you're unsure
Many machines colour-code each thread path to make identification easier. Common colour coding is shown below - always check your manual as colours can vary between models.
Left Needle
Yellow
Right Needle
Green
Lower Looper
Red
Upper Looper
Blue
Before adjusting tension - check these first
Tension adjustment should always be the second thing you try, not the first. These checks often resolve what looks like a tension problem without touching a single dial.
- Re-thread the machine completely before adjusting anything - incorrect threading mimics tension problems and no amount of dial adjustment will fix a threading issue
- How to Re-thread an Overlocker
- Make sure you're using good quality thread on all four paths - cheap or inconsistent thread behaves unpredictably under tension
- Check the differential feed is set to 1 as a starting point - differential feed affects how the fabric feeds through and can look like a tension issue if set incorrectly
- Always test adjustments on scrap fabric of the same weight as your project before returning to your work
What a balanced stitch looks like
On a correctly tensioned overlock stitch, the upper and lower looper threads interlock right at the edge of the fabric. The needle thread(s) should sit straight and even on the fabric surface with no loops or pulling on either side.
A balanced overlock stitch wraps neatly around the fabric edge with looper threads interlocking exactly at the edge - not on the top or underside of the fabric.
Identifying and fixing tension problems
Use the table below to match what you're seeing to the correct adjustment. Remember - make one small change at a time and test on scrap before making further adjustments.
| What you see | What to do |
|---|---|
| Looper threads intertwined on the wrong (under) side of the fabric | Reduce lower looper tension (red) / Increase upper looper tension (blue) |
| Looper threads intertwined on the right (top) side of the fabric | Reduce upper looper tension (blue) / Increase lower looper tension (red) |
| Left needle thread forming loops on the wrong side of the fabric | Increase left needle tension (yellow) / Reduce lower looper tension (red) |
| Right needle thread forming loops on the wrong side of the fabric | Increase right needle tension (green) |
| Seam gathering unintentionally | Differential feed set too high - reduce to between 0.7 and 1 |
| Seam waving or stretching unintentionally | Differential feed set too low - increase to between 1 and 2 |
Still having trouble? We're here to help.
If you've worked through the guide and your tension still isn't right, get in touch and our team will take it from there.