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Serger Sewing Basics
"How-to" Serger Skills for Beginner and Intermediate Sewers
By Carol Zentgraf
Annie'sCopyright © 2012 Annie's
All rights reserved.
Making Friends With Your Serger
What can your serger do for you? A lot! Maybe more than you can even imagine once you get to know how it works and its potential for creativity.
Sergers have come a long way since they were introduced to the home-sewing market in 1969. Today's machines are capable of multiple stitches and uses that still include, but surpass, the basic 2- or 3-thread overlock. Depending on the model, your machine may accommodate five or more threads, have special attachments and even include a computerized stitch advisor.
The basic function of a serger is really quite simple — it simultaneously sews a seam while it trims the fabric edges and encases them in neat, even stitches. Also, like a sewing machine, it has adjustable stitch length and width, adjustable presser foot tensions, and the capability of working with a variety of needles and threads. While there are many functions that a computerized sewing/embroidery machine can do that a serger can't, there also are many functions and techniques exclusive to the serger — making it a wonderful companion in your sewing room.
Unlike a sewing machine, sergers actually cut the fabric as they sew — stitching with a system of loopers and needles rather than with a bobbin and needle. Newer sergers also feature a differential feed system that eliminates stretching and puckering that can happen when you are stitching.
With a serger, you can create reversible projects with ease. The overlock finishes edges with stitches that look equally nice from each side, and the flat lock features decorative stitches on one side of the fabric and a ladder stitch on the opposite side.
It's easy to hem linens with rolled edges or to hem knits with the cover stitch. And of course, adding decorative embellishments to your serger projects is part of the fun. With the wide array of decorative threads available, you can create amazing accents for both the surface and edges of your fabrics.
Meet Your Machine
The first step in befriending your machine is to understand its features and how to use and control them. Take the time to familiarize yourself with the parts of your serger and how they work by reading your manual and comparing it to your machine. The following illustration is a generalized look at today's serger parts (Figure 1.1).
The Basic Overlock Stitch
Unlike a sewing machine that forms stitches with a needle and bobbin, the basic overlock is formed with needles and loopers. As the fabric is fed through the machine, the upper looper forms a loop that lies on top of the fabric, while the lower looper forms a loop that lies underneath the fabric, encasing the edge. The needle(s) thread catches and secures the interlocking loops to the fabric; they also lock at the fabric edge.
Mastering the Controls
Even if your serger has a computerized stitch advisor that shows you the exact settings for each stitch, it's important to know how the controls work and what they do so you can make adjustments when needed. Different fabrics and threads react differently to serger stitching, so you will very often be making adjustments in order to get that perfect stitch for your project. Once you get to know your serger, you won't be afraid to touch those tension dials or to make other adjustments. In fact, that will become part of the fun of serging!
Cutting Width & Stitch Width
One of the best time-saving features of a serger is the cutting system. It trims the fabric with two blades — one upper and one lower — that work like scissors to cut the fabric. On most sergers, the upper blade can be moved out of the way for cover stitches and some flat-lock applications.
The distance between the upper blade and the needle closest to the blade is the cutting width, or the width of the fabric edge that will be finished with the serged stitches. It is different than the seam allowance, which is the distance between the needle and the edge of the fabric. Usually when serging seams, part of the seam allowance will be cut off. On some sergers, the cutting blades may be adjustable to increase or decrease the cutting width. This may be a setting on a computerized machine, or you may need to manually move the blades. Consult your owner's manual to see if you have this option and how to use it.
One way to adjust the stitch width is by changing the needle position. Use the left needle only for a wide stitch and the right needle only for a narrow stitch. Consult your machine manual to see if it might also have controls to adjust the stitch width.
Another way to adjust the stitch width is by moving the stitch finger, which is where the loopers are placing the thread to form the stitch (Figure 1.3). Depending on your model, there may be a lever to adjust the stitch finger, or you may need to move it manually.
You will want to adjust the cutting width for some fabrics, certain stitches and to correct tension problems.
Like sewing machine stitches, the length of serger stitches can be adjusted. Simply set the stitch length on your machine as you would for a sewing machine. A normal overlock stitch length is 2.5mm on medium-weight woven fabric. Depending on your machine, you may be able to adjust the length from 0.8mm for rolled edges to 5mm for cover stitches. As a rule of thumb, you will want to decrease the length for lightweight or sheer fabrics and some metallic threads, and increase it for heavier fabrics and threads.
Differential Feed & Presser Foot Adjustment
A differential feed system has two sets of feed dogs — one in front of the other. The front set of feed dogs feeds the fabric under the presser foot, and the back set feeds it out of the serger. When you adjust the differential feed system, it sets the front set of feed dogs to feed more or less fabric under the foot, and to the back set of feed dogs. The uneven feeding gathers or stretches the fabric as it's serged, eliminating unwanted puckers or distortion. You can also use this feature to intentionally gather an edge or stretch it to create a lettuce-leaf edge.
Check your manual for specifics on adjusting the differential feed system. On most machines, the fabric is gathered more as the differential feed number is increased, and the fabric is stretched more as the number is decreased.
If your serger does not have a differential feed system, you can compensate for fabric weight and stretch by adjusting the presser foot pressure. A lighter pressure will allow heavier and stretchy fabric to pass between the feed dogs and presser foot, easily leaving a smoother seam. Refer to your owner's manual for more details.
Threading for Success
Many people dread threading a serger and cringe at the thought of a thread breaking. True, it is more complicated than threading your sewing machine, but it really isn't that difficult. The most important thing to remember is that the loopers and needles need to be threaded in the correct order to stitch properly. Some models thread themselves or can be threaded in any order, but most have specific requirements. Most manufacturers recommend that you thread the upper looper first, and then the lower looper and needles — in that order. Refer to the owner's manual for your model. Not threading your machine in the correct order will result in crossed threads that will break or cause a jam when you begin stitching.
Use serger tweezers as needed to help position the threads as you thread each looper and needle. It's also important to place all threads under the back of the foot before you begin stitching to ensure your beginning stitches sew correctly. The loopers and needles on a serger move at the same time making it easy for threads that aren't anchored under the foot to pop out of the needle or looper eye.
Don't despair if you have to rethread for some reason. Breaking a thread is bound to happen, and you will also need to change thread colors. Once you know how to thread your machine, it will be an easy task. If you are just changing colors it isn't necessary to completely rethread the machine. You can "tie on" the new thread to that which is already in your loopers and needles. Clip the threads close to the cones and place the new colors on the thread stand. Tie the new threads to the ends of the old threads with a tight square knot, leaving a 2- to 3-inch tail on the knot. Adjust the tension to zero on all needles and loopers, and slowly and carefully pull the threads through the guides. Knotted threads will go completely through the loopers, but stop and cut the knots when they reach the needles and then rethread the needle. Attempting to pull a knot through the needle may bend or break it.
This also works for some thread breaks. Depending on where the break occurs, you may have to rethread that looper or needle. When rethreading, make sure the threads are still placed in the correct order. For example, if the looper thread breaks, the needle thread(s) must be removed before rethreading the looper.
Next to improper threading, tension is the cause of most stitch formation problems — and the cause of most headaches — for serger users. Like threading, once you understand the effects of tension, it's easier to see how to make adjustments. When the looper and needle threads all form the stitch correctly, the tension is referred to as "balanced."
Most sergers have numbered tension dials, which makes tension adjustment relatively easy. Similar to your sewing machine, tension is adjusted for different weights of fabric. As a general rule: The more loft or thickness of the fabric, the looser the tension should be for needles and loopers. Fine or sheer fabrics need a tighter tension in both needles and loopers.
On a balanced 3- or 4-thread overlock, the upper looper threads form an "S" shape on the top of the fabric and lock with the lower looper thread along the edge. The lower looper thread should form a "V" for 3-thread stitching or a "Y" for 4-thread stitching on the underside of the fabric and lock with the upper looper thread along the edge.
Set the needle tensions first, and then the looper tensions. The reason for setting the needle tensions first is that the stitch formation is a combination of threads looped together. If one thread is too tight or loose, another thread can compensate for that tightness or looseness. Thus, for the best-looking seams possible, always adjust the left needle tension first because it affects the edges of the looper threads. Only adjust one tension dial at a time to balance tension.
Adjusting Tension on Overlock
The appearance of overlock is very similar when the upper looper tension is too tight and the lower looper tension is too loose. It also is very similar when the upper tension is too loose and the lower tension is too loose. Examine the stitch closely to see if you can determine whether it is being pulled or is simply too loose. Experiment with adjustments until the stitch is balanced.
The upper looper tension is too tight if the stitches are pulling the lower looper thread to the top of the fabric.
The lower looper tension is too tight if the stitches are pulling the upper looper thread to the underside of the fabric.
To correct, turn the corresponding tension dial to the left to loosen the looper tension.
The upper looper tension is too loose if the threads are wrapping around the edge to the underside or extending off the edge.
The lower looper tension is too loose if it is wrapping around the edge to the top side of the fabric or extending off the edge.
To correct, turn the corresponding tension dial to the right to tighten the looper tension.
The left needle thread tension is too tight if the outer thread is buried and pulling the lower looper thread into the fabric.
The right needle tension is too tight if the inner thread is buried and pulling the lower looper thread into the fabric.
To correct, turn the corresponding tension dial to the left to loosen the needle tension.
The left needle thread tension is too loose if the outer thread is lying on top of the fabric and leaving loops on the underside.
The right needle tension is too loose if the inner thread is lying on top of the fabric and leaving loops on the underside.
To correct, turn the corresponding tension dial to the right to tighten the needle tension.
Adjusting Tension on Rolled Edge
For a rolled edge, the upper looper thread should roll the edge evenly to the underside of the fabric. If the upper looper tension is too tight or the lower looper tension is too tight, the stitches will sit on the fabric surface without wrapping the edge. If the needle tension is too loose, the needle thread will form loops on the underside and the edge won't roll. Follow tension adjustments for the overlock to correct.
The stitches you can make with your serger depend on the number of threads it is capable of using at once. Refer to your machine owner's manual to set up the following stitches. Always remember to test your stitches on fabric that is similar to the fabric you're using. Do this to perfect your stitch before beginning your project.
2- & 3-thread overlock
Two-thread stitches are formed with one needle and one looper. Because the stitches are less bulky, they are ideal for lightweight knits and woven fabrics. They also have more stretch than stitches formed with three or more threads. Some serger models have a 2-thread converter for the upper looper that you will need to use; check your owner's manual and follow the directions for applying the converter and for any other instructions specific to your machine for 2-thread stitching. Three-thread stitches are the most commonly used and are suitable for a wide range of fabrics and applications.
Sometimes called an overedge stitch, the threads of this stitch overlock at the edge of the fabric only and do not form a seam.
Use this stitch for overcasting edges on lightweight or sheer fabrics, especially when using heavier threads. You also can use it for overcasting a single layer of medium-weight fabric.
This is the most popular stitch on the serger. Made with both loopers and one needle, the stitch can be wide or narrow depending on the needle position. A wide 3-thread stitch is made with the needle in the left position. A narrow 3-thread stitch is made with the needle in the right position.
Use a wide stitch for constructing seams or finishing edges on medium- to heavy- weight knit and woven fabrics. Use a narrow stitch for constructing seams or finishing edges on lighter fabric weights and in areas that will not receive much stress. Because the stitch is stretchable, it is especially useful for knit fabrics. For a decorative edge or seam finish, use decorative threads in one or both loopers and matching serger thread in the needle. Remember to test your stitch; you will probably want to lower your tension where you are using the decorative threads.
This stitch is frequently used for seams on ready-to-wear items. It is made using one needle and one looper. It is part of the 4- or 5-thread safety stitch, but it can be used alone for seams and decorative stitching. Depending on your machine, there may be a special looper or needle, or it may be part of the overlock system. The chain stitch is created by stitching with the wrong side of the fabric up. This creates the chain on the right side of the fabric and a straight stitch on the wrong side. A chain stitch is very easy to pull out by pulling the looper thread to unravel the seam.
Use this stitch to make a strong seam, for decorative topstitching on the fabric surface, for quilting, or without fabric to make belt loops, tassels or trim. It is also a very fast and functional stitch for alterations and basting because it provides a strong seam and yet is very fast and easy to remove!
2- or 3-thread flat lock & ladder stitch
Simple tension adjustments to a 2- or 3-thread overlock will give you a beautiful, decorative flat lock. It is made by using one needle and the upper looper for a 2-thread flat lock, or one needle and both loopers for a 3-thread flat lock. The needle tension is loosened so the needle thread is pulled across the underside of the fabric to the outside edge. The stitch can be made wide or narrow.
Excerpted from Serger Sewing Basics by Carol Zentgraf. Copyright © 2012 Annie's. Excerpted by permission of Annie's.
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