Taunton's Threads - For people who love to sew
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From the pages of Threads magazine Know Your Knits This guide to the confusing world of knit fabrics will help you select and use a knit with confidence I've found that many sewers shy away from knit fabrics, perhaps confused by the wide variety available (take a look at the samples in this article alone) or unsure of what kind of garment to construct from a particular knit. I believe the more you know about a fabric, the easier it is to evaluate how to use it. And knits are definitely worth getting to know—they are much easier to fit than wovens; resist wrinkles; in most cases, are wonderful to handle; and are extremely comfortable to wear. And these days you can find a remarkable range of knits in various fibers, among them, linen, silk, wool, Tencel, polyester, cotton, and cotton blends. When I’m asked how I know if a pattern will work with a certain knit, I have to say that the answer is ingrained in my fingers. Handling the fabric triggers now-intuitive knowledge derived from years of sewing with knits and absorbing every scrap of information I’ve ever learned about them. I’d like to provide you with an overview of basic facts about knit fabrics to help you develop your own cache of knowledge that will soon find its way into your fingertips.
Understanding the ways in which knit fabrics are manufactured will help you see why the topic of knits is so complex and why different knit fabrics behave in such dissimilar ways. Unlike a woven fabric, which is composed of a series of warp (lengthwise) yarns interlaced with a series of weft (crosswise) yarns, a knit fabric is made up of one or more yarns formed into a series of loops that create rows and columns of vertically and horizontally interconnected stitches. A vertical column of stitches is called a wale, and a horizontal row of stitches, a course. Although, in a woven fabric, the terms warp and weft refer to the direction of the two sets of yarns making up the fabric, in a knit fabric, these terms describe the direction in which the fabric is produced: A weft knit—which is what hand-knitted fabric is—is one made with a single yarn that’s looped to create horizontal rows, or courses, with each row built on the previous row. A warp knit is made with multiple parallel yarns that are simultaneously looped vertically to form the fabric (see the drawings above). Both warp and weft knits can be made either on a circular knitting machine, which produces a tube of fabric, or on a flat-bed knitting machine, which delivers flat yardage. Four basic stitches—All knit fabrics, even exotic novelty knits like laces and jacquards, whatever their structure, are composed of four basic stitches: a knit, or plain, stitch; a purl, or reverse-knit, stitch; a missed stitch, which produces a float of yarn on the fabric's wrong side; and a tuck stitch, which creates an open space in the fabric (see the drawings below).
Stretch is the bottom line All knits stretch to a greater or lesser degree, and this inherent give makes these fabrics comfortable, helps with fit, and is a big reason for choosing a knit over a woven. While the degree of stretch varies from one type of knit to another, the fabrics in a given category do not always stretch consistently. For example, a double-knit, known for its stability, can sometimes have more crosswise stretch than usual and not be stable enough for a given project. Hence, it’s imperative to assess the inherent stretch in a particular knit in order to make a good match between fabric and pattern. Always test-stretch a knit in the store (here’s where your fingers get into the act). Here’s how I do it: Since the greatest amount of stretch is usually in the crossgrain, I check this first. To assess the amount of stretch in the crossgrain, I grasp a single layer of the fabric between my left thumb and forefinger, then hold the fabric in the same way with my right hand about 4 in. away on the crossgrain. I put my hands and the fabric down on a ruler with my left hand at zero and start gently pulling the fabric along the ruler with my right hand. I stop pulling just at the point that I have to exert any effort (if I have to grip the fabric in my left hand more tightly, I know I’m over-stretching). By doing the test two or three times with the same knit, I get a feel for the fabric’s inherent stretch. Then I can either use a pattern designed for a knit with that amount of stretch or alter my pattern. Altering patterns for knits Select your fabric and determine its stretch, as explained above, before trying to alter your pattern, since the alteration will depend on the fabric’s stretch. Below are some general rules for altering patterns for knits: • If the fabric has no stretch, as with a firm jersey or rugby-type knit, pattern alterations are usually unnecessary. • The following are good starting points for alteration: If the fabric has only a little stretch (1/2 in.), take a total of 1/4 in. out of the pattern at both center front (CF) and center back (CB). If it has moderate stretch (1 in.), take a total of 1/2 in. out at both CF and CB. if it has generous stretch (2 in.), take a total of 1 in. out at both CF and CB. Any additional fitting adjustments can usually be made at the side seams or darts/princess seams. • Always make a muslin to fine-tune the necessary fitting adjustments, using an inexpensive knit fabric with similar stretch to that of your fashion fabric. Warp knits vs. weft knits Warp knits, which generally have a flat, smooth surface (though they can also be made with a pile), have little or no vertical stretch and varying degrees of crosswise stretch. Produced in a large variety of weights in a wide range of fiber types, warp knits are run-resistant and don’t ravel. With a few exceptions, weft knits have moderate to great amounts of crosswise stretch and some lengthwise stretch (some jerseys, however, have little or no crosswise or lengthwise stretch). On many weft knits, the edges may curl. As with warp knits, weft knits are made from many different fibers and come in many weights. If a stitch in a weft knit is broken, the fabric will tend to run, but a weft knit ravels only from the yarn end knitted last. Lots of knits (as well as wovens) are now being produced with the addition of spandex fiber to add stretch to the fabric. Garments made from fabrics with spandex can be comfortably fitted closer to the body. Although spandex imparts increased stretch and give to knits, it’s the ability to “recover” (or bounce back to its original state) that spandex adds that’s prized by manufacturers and sewers alike, since the resulting garments retain their shape. Now that you know some of the basic facts about knit fabrics, take a look at a few of common types of readily available knits in the samplings photos. Look for some of these knits in your fabric store, and try them out. As you gain a solid background of knit fabric facts through direct experimentation, you’ll relish sewing with these remarkable fabrics. A sampling of weft knit fabrics All weft knits fall into three basic categories: rib knits, which are a combination of knit and purl stitches; purl knits, which are made with purl stitches alone, and jersey knits, which are made with knits stitches on the front and purl stitches on the reverse (see the drawings above).  Double knitDescription: Made with two sets of yarns, this double-constructed fabric has fine ribs running lengthwise on both sides. Usually looks same on fabric’s face and reverse, making it reversible. Fancy double knits may have novelty stitch on fabric’s face and fine ribs on reverse. Properties: Heavy, firm; usually has almost no stretch in either direction. Good shape retention; cut edges don’t curl. Best use: Tailored garments, like jackets, suits, or sheath dresses. If particular double knit has some crosswise stretch, adjusting pattern (by cutting it slightly smaller in body girth) may be necessary.  InterlockDescription: Compound fabric made by “inter-knitting,” or interlocking, two simple ribbed fabrics, each made with single yarn. Has fine ribs running lengthwise. Fabric’s face and reverse look same, making it reversible. Properties: Almost no lengthwise stretch; more crosswise stretch than double knits or jerseys; fairly good shape retention. Raw or cut edges don’t curl; unravels only from end last knitted. Best use: Wonderful for T-shirts, turtlenecks, casual skirts and dresses, and children’s wear. Because of its crosswise stretch, use pattern designed for interlock knits, or be prepared to adjust pattern.  Jersey knitDescription: Also referred to as plain knit or single knit. Has distinct right and wrong sides, with fine ribs running lengthwise on fabric’s face, and semicircular loops running across reverse. Many variations of stitches and fibers create wide variety of single knits, ranging from delicate openwork to heavy, thick piled fabric. Properties: Little or no lengthwise stretch, varying amounts of crosswise stretch. Curls to fabric’s right side; cut edges unravel only from end knitted last. Best use: Jersey with little or no crosswise or lengthwise stretch (like most wool jerseys) can be used for skirts, blouses, and dresses without pattern adjustments. Jersey with crosswise stretch requires pattern adjustments or pattern designed for crosswise stretch.  Purl knitDescription: Double-faced, reversible fabric produced by intermeshed rows of knit and purl stitches, which appear as loops in crosswise direction. Sometimes called “Links-Links,” from the German word links (“left”), since knitting machine’s mechanism always moves to left. Properties: Usually heavy and bulky; stretches in both directions. Cut edges do not curl. Best use: Sweater-type garments, outerwear.  Rib knitDescription: Double-faced, reversible fabric with distinct vertical ribs on both sides, produced by alternating knit and purl stitches. Ribs can be small (1x1, that is, one knit stitch followed by one purl stitch), thick, (2x2 or 3x3), or uneven (1x3, for example). Properties: Little or no lengthwise stretch, but lots of crosswise stretch and good, natural recovery. Cut edges do not curl. Best use: Because of its elasticity, ideal for trimming other knits (and wovens). Garments made from rib knits are usually close-fitting and therefore use a pattern designed for knits. A sampling of warp knit fabrics Because of the multiple-needle configuration of warp-knitting machines, the warp knit fabrics produced can be very complex and intricate in structure; and they don’t fall neatly into groups or categories as weft knits do.  MilaneseDescription: Made from two sets of yarns knitted diagonally. Face has fine vertical rib, and reverse has diagonal structure. Properties: Lightweight, drapey, smooth texture, extremely run-resistant. Best use: Historically used for gloves and lingerie; makes lovely, soft blouses and eveningwear. May be a little difficult to find, but worth looking for.  RaschelDescription: Raschel-knitting machine produces wide variety of fabrics and can incorporate conventional or novelty yarns, thereby creating interesting textures and surface designs. Knits can be fine and lacey, highly patterned, and even piled. Properties: Runs gamut from dense and compact to open and lofty; can be either stable or stretchy, and single-faced or reversible. Best use: Almost any garment. Assessing amount of stretch, give, and recovery in a raschel knit is essential, since its nature is so diverse.  TricotDescription: Face has fine lengthwise ribs; reverse has crosswise ribs. Some machines can produce complex patterns, and some can incorporate a weft insertion (extra yarn inserted crosswise) for added texture or color. Properties: Some lengthwise stretch; almost no crosswise stretch. Usually soft and drapey; cut edges tend to curl. Best use: Besides traditional use for lining and lingerie, can be used for blouses and dresses. It’s essential to assess stretch of particular tricot for given project.
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