How to Use an Overlocker

How to use

Serger Anatomy

A serger stitches in a different way than a conventional sewing machine: it often has more than one needle and uses several loopers instead of one bobbin. This section covers the basic parts common to most sergers.

Front:

1. Foot pressure dial: adjustable foot pressure allows you to sew very lightweight or heavyweight fabrics
more successfully. This function may not be available on all models.

2. Differential feed dial: can be adjusted to prevent waving seams on stretch fabrics and to ensure pucker-free seams on lightweight fabrics. This function may not be available on all models (see Differential Feed, below).

3. Flatbed: with some sergers, it is possible to remove part of the bed to create a free-arm facility just as it is on some conventional sewing machines.

4. Needle plate: some sergers come with a second needle plate for stitching rolled hems; others have a special plate already built in – you need to pull a lever or press a button to bring it into play.

5. Stitch or cutting width dial: to regulate the width of the serged seam.

6. Presser foot: holds the fabric against the needle plate and feed dog. Like a sewing machine, the serger has different types of foot for different tasks, but serger and sewing machine feet are not interchangeable.

7. Needle: sergers may have one, two or three needles; use the recommended needle for your machine. Serger and sewing machine needles are not generally interchangeable.

8. Hinged case: the lower section of the body opens up to access the threading areas for the loopers. There is often a color-coded threading diagram inside.

9. Stitch patterns: illustrated reference for the types of stitch that can be sewn, with reference numbers that match those on the stitch selector.

10. Needle clamp screws: to release the needles when they require changing.

11. Looper thread tension levers: used to adjust the tension of the looper threads; there may be two or three, depending on the model. The loopers are located in the interior of the serger, accessed by a hinged door – they create the knitted look of the serger seam.

12. Needle thread tension levers: used to adjust the tension of the upper needle threads; there may be one, two or three, depending on the model.

Back:

13. Thread guide: each separate thread has its own guide. The threading runs are color-coded for ease of threading.

14. Stitch selector dial: for selecting the type of serger stitch to be sewn.

15. Stitch length dial: for regulating the length of the stitches.

16. Hand wheel: turn the hand wheel towards you (counterclockwise) to move the needle up and down slowly or to take the new thread through when rethreading using the knot method.

17. Power switch: to turn the machine on and off.

18. Power socket: socket for the power cable and the foot pedal; on some models there may be a separate socket for the foot pedal.

19. Telescopic rod: can be extended to take the thread guide hanger up to its full height or telescoped down for easier storage.

20. Presser foot lifting lever: this is behind the thread spool and is used to lift the presser foot to slide the fabric beneath, or when changing the foot.

21. Thread spool pins: hold the thread for the needles and the loopers, one for each threading run. Sergers use a great deal of thread, so larger spools or cones are a better option.

22. Thread guide hanger: each thread guide should be positioned above a corresponding cone beneath. Make sure the thread guide hanger is pulled up to its full height on its telescopic rod.

Cutting blades (not shown): a serger has a lower blade and an upper blade, which can be retracted if you want to stitch without trimming the fabric edge.

Differential feed

Differential feed is a variation of drop feed with two independent sets of feed dog, one before and one after the needle. By changing their relative motions, these sets of feed dog can be used to stretch or compress the material near the needle. This is very useful when sewing stretchy fabrics or for creating special effects, such as a lettuce edge. Differential feed is not found on sewing machines, although the dual feed or walking foot covers some of its functions, so it is worth considering a serger if you plan to work with stretchy fabrics often.

Threading the Serger

Since a serger uses between two and five spools of thread and has no bobbin, it is threaded in a different way than a conventional sewing machine. The basic principles are shown here.

Model Variation

Do make sure you follow the exact order of threading given in your machine's manual, which can vary from model to model, or you may find the thread keeps breaking when you try to stitch. Many people don't consider a serger because they are afraid it will be too difficult to thread, but once you understand the principles of how the machine works you will soon find threading quite easy.

Threading up using the knot method
The easiest way to thread a serger with existing threads in place is to knot the new thread to an existing thread and pull the new thread through, either by winding the handwheel or pulling through by hand.

Tie the new thread to the end of the old using a flat reef knot. To tie a reef knot, take the ends of the thread, one in each hand. Take the left end over the right end and under, so the left end is now on the right and vice versa. Take the end now on the right over the one on the left and under. You should now have a symmetrical flat knot. Trim the thread ends, but not too close to the knot as it may pull undone.

Make sure the presser foot lever is up and loosen the tension dials to 0, then wind the new threads through the serger using the handwheel, or pull each through gently one at a time from above the needle or looper eye. Ease the knot gently at key points – such as through the tension plates. On the needle threads, stop the knot before the eye of the needle, snip it off and thread the needle by hand. If not done automatically, reset the tension when the machine is correctly rethreaded.

On the diagram below the two needles are threaded in red and blue, the upper looper in yellow, the lower looper in orange and the chain-stitch looper in green.

Threading from scratch
If the thread has completely run out on one or more of the runs, you will need to thread up from scratch. Early sergers were quite complex to thread, but modern types are much easier and some even have a self-threading mechanism. Sergers must be threaded in a certain order because of the way the threads pass across one another. If you thread them in the wrong order, as you move the hand wheel to access the threading runs the needle threads can get tangled around the looper threads, and these will break when you begin to stitch. Check your manual to be sure of the correct threading order.

To thread the first looper: take the thread from the spool, up through the corresponding eye on the thread hanger and down to its matching thread guide on top of the machine. Slide the thread through the tension mechanism and then into the thread guide directly below the tension dial or lever. Slip the thread into the next guides in order along the threading run, which is usually indicated by color-coded dots or a colored line. Take the thread through the eye of the looper, then pull the end towards the back of the serger, leaving around 6in (15cm) hanging free. Repeat for the other loopers, following the corresponding color-coded runs.

To thread the first needle: take the thread from the spool, up through the corresponding eye on the thread hanger and down to its matching thread guide on top of the machine. Slide the thread through the tension mechanism and then into the thread guide directly below the tension dial or lever. Take it under the guide to the left then over the top thread path, following the color-coded thread run. Take the thread through the wire guide at the top of the needle and then through the eye of the needle. Pull the end towards the back of the serger, under the foot, leaving around 6in (15cm) hanging free. Repeat for the other needle or needles, following the corresponding color-coded runs.

Avoiding threading problems

• If you have just purchased a new machine it may have threads in place running through the machine with the ends hanging from the loops on the thread guide hanger towards the spool pins. Do not remove, as they are there to help you thread the machine the first time. Use the knot method (see opposite page).
• Never set the machine stitching to work the knots through, as they can easily damage the mechanism.
• If threading from scratch, the loopers should always be threaded before the needles. Some sergers are best threaded in the following order: lower looper; upper looper; right needle; left needle. On others the order is upper looper; lower looper; right needle; left needle. Check your machine's manual.
• If the looper thread breaks, you will have to unthread the needle threads from the eye of the needle before trying to rethread the looper.