Which Serger Stitch When?
Serged stitches add stretch and strength to seams, simplify edge-finishes, and even embellish a garment. But there are so many stitches to choose from, it's hard to know which stitch to use on which fabric or when not to serge at all. Some of these questions can be answered by learning the standard serger stitches and their attributes.
Be aware that not all sergers can make every stitch, so check the machine's manual to see what it can do. And if you're shopping for a new serger, make sure the model you choose has the stitches you want.
To serge or not to serge
To decide whether to use your serger instead of a conventional machine, it's important first to understand the difference in these two types of stitches: On a serger, the looper threads are looped and interlaced-in effect, knitted-with the needle thread(s); on a standard machine, the bobbin thread locks with the needle thread.Â
Next think about your fabric, how you'll use it, and how often you'll wash it. Will it be a knit you'll wash frequently? A woven destined for sportswear and a one-season life span? Or a sheer, crinkled fabric for a loose-fitting garment? In all these cases, the serger is the way to go for seaming and edge-finishing. But if you're making a straight wool skirt or a linen blazer, serging the seams will yield bulky lines rather than the smoothness of pressed-open seams. And if you plan to line your garment, finishing edges with the serger is a waste of thread because all seams will be enclosed.
Selecting a serger stitch
When you do opt for a serged seam or edge-finish, choose the stitch that matches the needs of your garment. Keep in mind that a serger stitch with fewer threads can have a lot of strength and stretch. Stitches with more threads tend to be bulkier rather than stronger, though there are exceptions, like the superstretch, three-thread wrapped stitch. And stitches incorporating the chainstitch make a stable, nonstretchy seam.
As a rule, use a narrow stitch with fewer threads for lightweight fabrics, wrapped stitches for maximum stretch on knit seams, overlock stitches for standard seams on knits and wovens, and wider overlock stitches with the most threads for ravelly or bulky fabrics. Flatlock stitches are wonderful for sportswear that needs to be comfy on the inside, and rolled-hem stitches finish delicate sheers beautifully. Thread tensions may need adjustment depending on the particular fabric and for flatlock and wrapped stitches.
To reduce the bulkiness of serged seams that use a lot of thread, use a long stitch length. Be sure to experiment with stitch length on a sample first. If the stitches are too far apart, the resulting seam may not be strong enough, especially on loosely woven fabrics.Â
On many machines, for two- and three-thread stitches, you can choose between using the left needle for a wide stitch, the right for a narrow stitch, or using the machine's rolled-hem function to produce a very narrow stitch (see the photo at left). And don't forget embellishment: Take advantage of the fact that a serger's loopers don't pierce the fabric, meaning you can use heavier, decorative thread in one or both loopers to turn a seam or edge-finish into a design element.
The names of the stitches may be confusing at first, and may vary slightly from manual to manual, but all relate to how the stitches are formed. Two-thread stitches are generally called overedge, or overcast, because the threads don't interlace at the needle. Three-, four-, and five- thread stitches are referred to as overlocked because the needle thread interlaces with the loopers to form a knot at the needle line. And when the looper thread completely encircles the edge of the fabric on some two- and three-thread stitches, the stitches are called wrapped.
Once you become familiar with the wide variety of stitches offered on sergers, you'll develop a sense of when to use a stitch. Then use them often so your garments will look better and last longer. Here are just a few of your options.
Configuration: Needle thread lies across bottom of fabric and looper thread across top; threads intersect at edge.*
Qualities: Lightweight and stretchy. Best uses: Superb as edge-finish onÂ delicate fabrics. Narrow-width stitch is good alternative to rolled hem.
Configuration: Same as over-edge but with fabric layers pulled apart to lie flat. Sewing with wrong sides together placesÂ lower-looper thread on outside; sewing with right sides together places needle thread on outside.*
Qualities: Stretchy and strong; reversible stitch that looks goodÂ on both sides.Â
Best uses: Seams on sportswear, outerwear, and sheers (in narrowest width); decorative stitch on wovens and for piecing.
Configuration: Lower-looper thread wraps around fabric's edge from front to back, locking with needle thread at needle line.*
Qualities: Strong and stretchy. Best uses: Seams on lightweight fabric, or edge-finish (nice with decorative thread in looper).Â
Best uses: Seams on sportswear, outerwear, and sheers (in narrowest width); decorative stitch on wovens and for piecing.Â
Two-thread rolled hem:
Configuration: Same as two-thread wrapped in narrowest width.Â
Qualities: Narrow and strong.Â
Best uses: Edge-finish on lightweight and sheer fabrics. Not generallyÂ used as seam.
Configuration: Special chain needle interacts with separate forward chain looper. Needle thread appears as straight stitch on top of fabric, looper thread lies in coil between knots of needle thread on bottom.*
Qualities: Not stretchy, unravels easily.Â
Best uses: Basting, decorative topstitching, and chain production (chain must be started in fabric but can continue without fabric).
by: Millie Schwandt
excerpted from Threads #80, p.41