Overlock foot vs an overlocker

What an overlock foot does

An overcasting foot has a small metal bar or pin on the right hand side. You line the raw fabric edge up against a guide, and when the needle swings right on a zigzag or overcast stitch, the thread wraps over the pin and the edge rather than pulling it into a ridge. The result is a flat, wrapped edge that stops fraying.

Most machines offer one or more overcast stitches designed for this foot, some of which look similar to a 3 thread overlock from the top. The foot works with the machine's normal upper thread and bobbin. Our guide to sewing machine feet shows the shape of this and other common feet.

What a real overlocker adds

An overlocker (called a serger in the US) uses one or two needles and two loopers to form a chain of looped threads around the edge, while a knife trims the seam allowance just ahead of the needles. Seaming, trimming and neatening happen in one pass at high speed.

Overlockers also have differential feed, which lets you stop knit seams from stretching out or make light fabrics gather, and many can sew rolled hems. The looped stitch stretches with knit fabric, so it is the standard finish for T-shirts, leggings and sportswear. Read sewing machine vs overlocker and overlocker differential feed explained for more.

Side by side

The table summarises the practical differences for home sewing.

When the foot is enough

If you mostly sew woven fabrics such as cotton, linen and polycotton and want tidy insides on cushions, curtains and simple garments, an overcasting foot with a good overcast stitch is often enough. Trim the seam allowance neatly first, then sew with the edge against the guide.

It is also a sensible way to start if you are not sure you will sew enough to justify an overlocker. Buy the foot designed for your machine where possible, as feet are not universal. See are sewing machine feet universal for the shank question.

When to buy an overlocker

Consider an overlocker when you sew a lot of knits, make clothes regularly, or find yourself spending more time neatening seams than sewing them. Dressmakers who move from wovens into jersey usually notice the difference first.

Look for easy lower looper threading, colour coded guides, differential feed and a free arm if you hem sleeves. Our best overlockers for beginners guide compares models built for first time owners, and how to thread an overlocker explains the part people find hardest.

See overlockers for beginners →

How to get the best edge with an overcasting foot

A few habits make a big difference to the finish. Test each step on a scrap of the same fabric before working on the garment.

1. 1

   Trim the seam allowance straight and even, as the foot does not cut.

2. 2

   Select an overcast stitch recommended for the foot and check the stitch width so the needle clears the pin.

3. 3

   Turn the handwheel by hand for the first stitches to make sure the needle does not hit the foot.

4. 4

   Keep the raw edge running against the guide without pushing or pulling the fabric.

5. 5

   Use a ballpoint or stretch needle on knits and lengthen the stitch slightly if the edge waves.

6. 6

   Press the finished edge flat to settle the stitches.

Note:Always check the needle clears the foot before sewing at speed. A needle striking the pin can break and damage the needle plate.

Frequently asked questions

Does an overlock foot make a sewing machine an overlocker? No. It helps the machine wrap an edge with an overcast stitch, but there is no knife or looper, so it cannot form a true overlock stitch.

Which stitch should I use with an overcasting foot? Use the overcast stitches your manual recommends for that foot, and make sure the stitch width is set so the needle clears the pin.

Can I sew jersey with an overlock foot? Yes, with a ballpoint needle and a stretch overcast stitch. For lots of knitwear, an overlocker gives faster, stretchier seams.

Is it worth buying an overlocker as a beginner? Not as a first machine. Learn on a sewing machine first; add an overlocker when you sew enough knits or garments to need it.