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.

What you'll need

• Manual or threading chart: order matters.
• Tweezers or looper threader: for tight spots.
• Overlocker thread cones: four.

Step by step

1. Raise the presser foot and turn the handwheel so the needles are up.
2. Thread the upper looper following its colour guide.
3. Thread the lower looper. Check your manual for the order of upper and lower.
4. Thread the needles last, right then left (on most machines).
5. Pull all tails under the foot to the back.
6. Sew a test chain.

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 1 November 2026. We read these; we did not test the products ourselves.

1. The Sewing Directory: How to Thread an Overlocker
2. Tilly and the Buttons: The Fast Way to Thread Your Overlocker or Serger (with Video!)
3. YouTube: Threading the Overlock Machine (University of Derby)
4. YouTube: How To Thread A Serger - Overlock Machine (Sewing Parts Online)
5. YouTube: How to thread an Overlocker 2504D | Brother Australia (BrotherAU)