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Sergers: Thread: Functional and Decorative

The serger has been a boon to the home sewer who wants to continue sewing but has strict time limitations. A serger uses more thread than a traditional ma chine, so it’s technically more expensive, but in today’s fast-paced world we need to put value on our time. This increased use of thread is offset by the hours of time saved, as well as the improvement of the final product.

Quality and Packaging

I believe using good thread is a necessity. The influx of cheap thread sold especially for sergers is sometimes exactly that—cheap thread. Cheap isn't always a bargain. Poor-quality thread will cause breakage, skipped stitches, and tension problems.

The characteristics of quality thread are:

Uniformity—Uniform thread is smooth and even. If it has slubs, they are not hard chunks, but are small (Fig. 9.1). The thickness should remain the same throughout the spool. If a big slub comes off the spool and hits the tension wrong, it will slide around the dial and pull the thread out of the separating plates instead of through it (Fig. 9.2). This is why the tension occasionally goes haywire in mid-seam.

Fig 9-1: Irregular thread

Fig. 9.2: Thread stubs will pull thread out of tension

Flexibility—Flexible thread bends easily and isn't stiff. The loops on the fabric are even and soft and the over cast isn't prickly.

Strength—Because of the speed of an overlock, the thread takes more abuse. If the thread is uneven or has weak spots, it will break.

Hint. Be wary of a “million” yard cone advertised for $1.99. It is generally a waste of time and money because it doesn’t work well on the machine.

Check in sewing-machine stores to find a large assortment of good-quality thread. They have a vested interest in making sergers perform at their best. You will find the variety you seek and the guidance on use that will make your serging successful.

Although thread quality isn't quite as important on an overlock as on a traditional machine, it can't be completely ignored. In addition to the quality of the thread, there is another variable: the way the thread is wound onto the spool or cone. Even this seemingly minor difference can make a big change in the serger’s performance.

There are two ways to wind thread onto a spool. The best way for an over- lock is to use an easy-release spool (Fig. 9.3). This thread, whether on a cone or small spool, has been wound in a diamond-shaped pattern that allows it to be pulled easily from the top.

Fig. 9.3 Easy release wind; Diamond wrap pattern

The drawback of easy-release thread is the tendency of the individual strand to slide too easily down the side of the holder. The more slippery the thread, the more frequently this happens. The thread can catch under the bottom of the spool or cone and no longer unwind. The stitches will pucker and the thread will eventually break. This can be prevented by using plastic thread nets that slip over the whole spool or cone. These are available at most dealers and can be used on any brand of serger.

The other method of winding thread is called a traditional wind (Fig. 9.4). (Dual Duty is wound on a traditional spool.) This thread is wound from the top down and then the bottom up, one thread right next to the other. It has a small slit in the end to hold a loose thread end.

Fig. 9.4 Traditional spool

The problems caused by this type of wind are twofold: (1) As the thread unwinds from the top, it keeps catching on that little hook and can snap. (2) As the thread goes from the bottom up, it has to pull itself over the next rung of thread, yet when it winds from the top down, it can release easily. The result is 6” of normal stitching and 6” of too- tight stitching.

To alleviate both of these problems, overlocks come with spool caps. These are shaped like tiny Frisbees or wagon wheels. You should have one for each spool holder. The caps are meant for use with traditional spools of sewing-machine thread. The spool caps sit on top of the spool and protect the ends. They also force the thread out and up, which evens out the tension.

Note: Cheap thread problems sometimes show up after the garment is assembled and washed, If shrinks and puckers as it's laundered.


Only the needle thread on a seam shows on the right side of the fabric, so it's the only thread that must match if the inside isn't going to be visible or on display. Therefore, you can use a blending color on large cones on the loopers and small matching color spool(s) on the needle(s).

A traditional spool of thread can be used if you really need to match a color. You will find the tension is more erratic and more difficult to adjust when you mix thread brands. Use the easy- release spools whenever possible for the best results.

Varieties and Fibers

The most common thread used in an overlock is mid-weight polyester. Polyester has the stretch and strength that are essential in the fast-moving sergers. These threads come in a variety of colors. Standard thread for sewing machines can also be used, especially the easy-release spools. Polyester also comes in finer weights for use with lingerie and other fine but stretchy fabrics.

Use cotton thread when strength isn't as important as softness and flexibility. Because cotton isn't as strong as polyester, work at a slower-than-normal speed. For a very fine edge on crepe de chine, try using extra-fine cotton. But sew carefully and use a reduced speed.

The manner in which a serger makes a stitch and the large eye on the loopers allow you to use a range of threads and yarns that a traditional sewing machine couldn’t handle. The serger needle can be threaded with a thread of matching or contrasting color or a clear nylon monofilament. Be sure the washability of the strand is compatible with your fabric.

Hint: Clear nylon thread is some times prickly in a seam, so experiment and adjust placement if necessary.

The maximum thickness of a strand to be put through the looper is approximately the same as fingering yarn. Here is a list of possibilities:

1. Yarn and string—Cotton, wool, linen, silk, jute, synthetics, and metallics or any combination of fibers

2. Floss—Embroidery floss, perle cotton in an assortment of weights, metallic filament, and untwisted nylon (called woolly or fuzzy) (Be ware: nylon melts under a hot iron.)

3. Monofilament—Ribbon, very fine cord, and clear or translucent thread is made of nylon and is especially good for blind hems and the application of trims

4. Mixtures of threads

The resistance of these different overcast strands will vary greatly. It is imperative that you practice and adjust all the tensions. Often when using the unusual looper threads, you will also have to change needles and tensions. Because there are so many variables, the only way to discover the right set ting is to experiment.

If any of these threads or yarns don't have enough strength to be used alone in a serger because they repeatedly break, use a strand of strong polyester or nylon thread at the same time. Just thread them both through the ma chine, including the tension, and handle them as one thread.

This list is only a beginning. Now that you arc starting to understand how your serger works and how easy it's to adjust, you can spread your wings. Develop an eye for seeing any new string as a possibility.

Look for new ideas in yarn shops, needlework shops, craft stores, and fabric stores in the trim, ribbon, and bridal accessories departments.

Thread Guides and Supports

Most machines have some type of cone supports (one for each thread spool) made of rubber or plastic. They slide over the spool pin for use with large cones and widen the base of sup port, preventing the cones from wobbling around.

When you work an overlock, the telescopic extension must be extended to the top. If the thread guides are not aligned properly, your tension will be thrown off.

Some machines have a sliding thread bed that must be pushed from one side to the other to be in working position. For storage and travel, they slide to a safety position. If this thread bed isn't in the operating position, the tension will not function properly.

Rethreading or Tying On

In section 8, you learned how to thread your serger from scratch. Usually it’s not necessary to rethread the entire machine. I tie the new threads onto the old threads and run them through the overlock. This makes changing your thread faster and easier.

Even when we know how to change and proof the thread, it's still a pain to redo the entire machine so here are five tips to make the change foolproof:

1. Don’t try to pull a knot through the eye of a needle. It is too easy to bend the needle and will cause it to break. It is much simpler to snip the thread just above the eye of the needle and rethread the needle.

2. Cut the looper threads at different heights above the tension mechanism so you can control the timing of the knots passing through the tension (Fig. 9.5).

Fig 9-5 Cut looper threads at different heights

3. Use an overhand knot (Fig. 9.6). Hold the two ends together, make a loop, put the ends through the center of the hole, pull tight, and trim ends to 1/4”.

Fig. 9.6 Overhand knot

4. Use a reduced speed.

5. Reduce the tension as the knot travels through each mechanism or the thread might pull itself out of the tension.

Thread Consumption

Each of the cones on a serger uses up different amounts of thread. The loopers use thread about three to five times as fast as the needle. If you have a chain or safety chain needle to the left, it will use the thread at about the same rate as the loopers. The reason I make this point is that you must be conscious of rotating your threads some time about halfway through your project.

The wider the overcast seam, the faster the looper thread will be used up. A thicker looper thread or yarn will also add to the amount of thread the machine will use.

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Thursday, 2009-04-30 18:44