Differential feed: no more wavy knit seams

Differential feed changes how fast the front and back feed dogs move. Turn it up (above 1) to stop knits stretching into wavy seams; turn it down (below 1) to stop fine fabric puckering.

Pinny's tip
Don't use differential feed on thick, non-stretch fabric such as denim; Brother warns it may damage the fabric.

What you'll need

• Overlocker with differential feed: most have a dial.
• Knit and woven scraps: to test.

Step by step

1. Start at the normal setting of 1.0, where the front and rear feed dogs move at the same speed.
2. Sew a test on your fabric.
3. If the seam waves or stretches, raise the setting from 1.0 towards 2.0; the stretchier the fabric, the higher.
4. If lightweight fabric puckers, lower it below 1.0.
5. Re-test until the seam lies flat.

Common mistakes

• Pulling the fabric. Stretches the seam regardless.
• Big jumps. Change in small steps.
• Leaving it high afterwards. Reset to 1 for the next project.

Watch it done

• Differential Feed on the SINGER® 14CG754 Serger by Singer Sewing Company on YouTube. Opens on YouTube; the video belongs to its creator.
• How to Avoid Annoying Wavy Seams in Knit Fabrics by Line of Selvage on YouTube. Opens on YouTube; the video belongs to its creator.
• Bernina L 460 Serger Manual - Differential Feed by J Stern Designs 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.

1. Brother USA support: Explanation of the differential feed and how to use it
2. YouTube: Differential Feed on the SINGER® 14CG754 Serger (Singer Sewing Company)
3. YouTube: How to Avoid Annoying Wavy Seams in Knit Fabrics (Line of Selvage)
4. YouTube: Bernina L 460 Serger Manual - Differential Feed (J Stern Designs)