How to thread an overlocker
Follow the colour-coded order in your manual, usually upper looper, lower looper, then the right needle and left needle. Threading in the wrong order is a common reason threads break or the stitch won't form.
Pinny's tip
Tie-on method: when changing colour, cut old threads at the cones, tie the new ones on and pull them through.
Tie-on method: when changing colour, cut old threads at the cones, tie the new ones on and pull them through.
What you'll need
- Manual or threading chart: order matters.
- Tweezers or looper threader: for tight spots.
- Overlocker thread cones: four.
Step by step
- Raise the presser foot and turn the handwheel so the needles are up.
- Thread the upper looper following its colour guide.
- Thread the lower looper. Check your manual for the order of upper and lower.
- Thread the needles last, right then left (on most machines).
- Pull all tails under the foot to the back.
- Sew a test chain.
Watch
Threading the Overlock Machine (17:08)
By University of Derby · Open on YouTube
The video this technique page has always pointed to, a 17-minute one from University of Derby. Embedded from YouTube with credit; we don't host it. It only loads when you press play.
Common mistakes
- Threading needles first. Loopers usually first.
- Threads not in tension discs. Hold the thread at both sides and pull it down between the tension discs, like dental floss, until it clicks in.
- Presser foot down while threading. Discs stay closed.
Watch it done
- Threading the Overlock Machine by University of Derby on YouTube. Opens on YouTube; the video belongs to its creator.
- How To Thread A Serger - Overlock Machine by Sewing Parts Online on YouTube. Opens on YouTube; the video belongs to its creator.
- How to thread an Overlocker 2504D | Brother Australia by BrotherAU on YouTube. Opens on YouTube; the video belongs to its creator.
Sources
All checked November 1, 2026. We read these; we did not test the products ourselves.