# Overlocker differential feed explained

Source: https://stitchandhem.co.uk/blog/overlocker-differential-feed-explained
Published: 2026-10-12
Publisher: Stitch and Hem

**In short:** Differential feed uses two sets of feed dogs, one in front of the other, that can move at different speeds. Setting the front feed faster than the back (a ratio above 1.0) eases fabric in and stops knits stretching into wavy seams. Setting it slower (below 1.0) holds fabric taut and stops fine wovens puckering. Normal 1.0 suits most stable fabrics.

If your overlocked seams on jersey come out rippled like lettuce, or fine fabrics pucker along the edge, the fix is usually not tension but differential feed. Almost every modern overlocker has it, yet the dial is easy to ignore. This explainer covers what the two feed dogs do, what the numbers on the dial mean, the settings to start with for common fabrics, and how to use differential feed on purpose for gathering and lettuce edge hems.

## What differential feed is

A standard sewing machine has one set of feed dogs that moves fabric under the presser foot. An overlocker with differential feed has two sets: a front feed dog that takes fabric in, and a rear feed dog behind the needles that moves it out the back. The differential feed dial changes how far the front feed dog moves compared with the rear one on each stitch.

When both move the same distance, the fabric passes through at an even rate. When the front moves more, extra fabric is pushed under the needles and eased in. When the front moves less, the rear feed pulls the fabric slightly, which holds it taut as it is stitched. This simple difference is what controls stretching and puckering.

## What the numbers on the dial mean

Differential feed is usually shown as a ratio. On many overlockers the range runs from about 0.5 or 0.7 up to 2.0, with 1.0 or N marking the neutral setting. The exact range and markings vary between models, so check the manual for yours.

A setting of 1.0 means both feed dogs move equally. Above 1.0, for example 1.5, the front feed moves one and a half times as far as the rear one, gathering the fabric slightly. Below 1.0, for example 0.7, the front moves less than the rear, stretching the fabric a little as it sews.

| Setting | What the feed dogs do | Typical use |
| --- | --- | --- |
| Below 1.0 (around 0.7) | Front feed slower than rear, fabric held taut | Lightweight wovens, silky fabrics that pucker |
| 1.0 (neutral) | Both feeds move equally | Stable cottons, medium wovens, most general sewing |
| Around 1.3 to 1.5 | Front feed faster, fabric eased in | Jersey, T-shirt knits, sweatshirt fleece |
| Up to 2.0 | Front feed much faster, fabric gathered | Very stretchy knits, ribbing, gathering on purpose |

Differential feed settings at a glance

## Fixing wavy seams on knits

Knit fabrics stretch as the feed dogs and presser foot move them, and the overlock stitch locks that stretch in place. The result is a wavy, rippled seam or hem that will not lie flat. Increasing the differential feed above 1.0 pushes more fabric under the needle, which compensates for the stretch.

Start at around 1.3 for medium weight jersey and test on a scrap of the same fabric, cut on the same grain as your seam. If the seam still ripples, raise it in small steps towards 1.5 or higher. If it starts to look gathered, go back a step. Lightly reducing the presser foot pressure, if your overlocker allows it, can also help. For more on sewing stretch fabrics, see our guide to [sewing stretch fabric](https://stitchandhem.co.uk/blog/how-to-sew-stretch-fabric).

1. Cut a test strip of the knit at least 20 cm long, on the same grain as your seam.
2. Overlock it at 1.0 and check whether the edge ripples.
3. Raise the differential feed to around 1.3 and sew another test.
4. Continue in small steps until the seam lies flat without gathering.
5. Write the setting on a note with the fabric name for next time.

## Fixing puckered seams on wovens

Fine, lightweight wovens such as lawn, voile, satin and polyester linings can do the opposite: the fabric bunches as it is fed, and the seam puckers. Lowering the differential feed below 1.0 makes the rear feed slightly outrun the front, which holds the fabric taut and smooths the seam.

Try around 0.7 to 0.8 on a test scrap. Combine this with a fresh, fine needle of the type your overlocker's manual recommends and slightly lower thread tensions if the stitch still draws up. Hold the fabric gently in front of and behind the foot without pulling it, and let the feed dogs do the work.

Note: Switch off and unplug the overlocker before changing needles, opening the looper cover or clearing trimmings from around the feed dogs and knife. If the feed dogs stop moving or the machine jams repeatedly, have a qualified sewing machine engineer check it.

## Using differential feed on purpose

Differential feed is not only for correcting problems. Turning it up to the maximum on a lightweight woven gathers the fabric as you overlock, which is useful for ruffles and gathered skirts on light fabrics. The amount of gathering depends on the fabric, so test first.

Turning it down below 1.0 on a stretchy knit while gently stretching the edge produces a lettuce edge hem, the fluted, wavy finish often used on T-shirt sleeves and children's clothes. This works best with a narrow rolled hem or a short stitch length. If you are choosing an overlocker with a wide differential feed range for these effects, our [best overlockers for beginners](https://stitchandhem.co.uk/best/best-overlockers-for-beginners) guide compares models, and the [coverstitch and combination overlockers](https://stitchandhem.co.uk/best/best-coverstitch-and-combination-overlockers) guide covers machines that also hem knits professionally.

[Compare overlockers for beginners](https://stitchandhem.co.uk/best/best-overlockers-for-beginners)

## Differential feed or tension?

It is easy to confuse the two because both affect how a seam looks. A simple rule: if the seam is wavy or puckered along its length, look at the differential feed first. If the threads themselves look wrong, such as loops hanging off the edge, looper threads not meeting at the edge or needle threads loose, look at the thread tensions. Our [overlocker threading guide](https://stitchandhem.co.uk/blog/how-to-thread-an-overlocker) covers threading problems that can look like tension faults.

Stitch length also plays a part. A longer stitch can reduce waviness on knits, while a shorter stitch gives a denser edge. Change one setting at a time so you know which adjustment made the difference.

## Frequently asked questions

**What should differential feed be set to for jersey?** A good starting point for medium weight jersey is around 1.3 to 1.5. Test on a scrap and adjust in small steps until the seam lies flat without gathering.

**Why are my overlocker seams wavy?** Wavy seams on knits usually mean the fabric is stretching as it feeds. Raise the differential feed above 1.0, and if your machine allows it, reduce presser foot pressure slightly.

**Does a coverstitch machine have differential feed?** Most coverstitch and combination machines include differential feed, because hemming knits with a coverstitch has the same stretching problem. Check the specification of the model you are looking at.

**Can I use differential feed on a regular sewing machine?** No. Standard sewing machines have a single set of feed dogs. The closest equivalent is a walking foot, which feeds the top layer evenly, but it works differently from differential feed.

## Buying guides on this topic

- https://stitchandhem.co.uk/best/best-overlockers-for-beginners
- https://stitchandhem.co.uk/best/best-coverstitch-and-combination-overlockers
- https://stitchandhem.co.uk/best/best-sewing-machines-for-dressmaking