All models of the single and straight-line sewing machines for fabric density- needle and two-needle straight-line sewing machines, with needle and lower material transport, are divided into two subclasses according to the density of sewing materials: models for light and medium fabrics and models for medium and heavy fabrics. For each brand and individual model, subclasses are labeled differently and are far from always obvious. Both letters and numbers can be used for designation, although sometimes completely different numbers are used. For example, Typical GC 6150MD – light and medium fabrics, Typical GC 6150HD – medium and heavy fabrics; Brother S-7100A-403 – light and medium fabrics, Brother S-7100A-405 – medium and heavy fabrics; Minerva M5550-JDE – light and medium fabrics, Minerva M818-JDE – medium and heavy fabrics. A good pair of sewing scissors is simply necessary for both an experienced tailor
Straight-line sewing machines
Structurally, machines of different subclasses are largely similar, but can have up to 20 different parts, mainly related to stitching formation: needle bar, needle holder, thread guide, needle plate, gear rack, presser foot, stitch length adjuster, thread tension adjuster, main eccentric, connecting rod and Others also sewing machines can have different shuttles, and models for medium and heavy fabrics are additionally equipped with a pre-tensioner. There is a specificity in working with thin and dense materials. For example, a needle plate, a specific needle hole, plays an important role in loop formation: after the material is punctured, reaching the bottom point, the needle returns to its original position, at this moment a loop is formed, which is then captured by the hook nose and interlacing with the bottom thread forms a stitch. On different materials, the loop is formed in different ways – if the fabric is thin and the hole diameter is too large, the material will simply “fall through” into the eye, preventing the formation of a loop of the required size, which will entail skipping of the stitch. The needle bar stroke in the subclass for medium and heavy materials is also increased for a reason – this is a necessary condition for working with dense fabrics. These and many other nuances serve as the basis for subclassing straight-line machines.
Best models sewing machine
In the bulk, models for light and medium fabrics have the following technical characteristics: maximum sewing wiki speed: 5,000 st / min; maximum stitch length: 4-5 mm; needle bar stroke: 31 mm; needle system: DBx1; needle hole diameter: 12-20 mm; tissue density: up to 250 mg / mm³; fabric bag height: up to 6 mm. Thin knitted fabrics and woven materials, such as organza, tulle, culinary, chiffon, chintz, batiste, poplin, satin, Bologna, interlock, jacquard, be reflex, velour, crepe, ottoman, cashmere, and most often are sewn on sewing machines of this subclass. other
Models for medium and heavy fabrics have the following technical characteristics: maximum sewing speed: 3,500 st / min; maximum stitch length: 5-8 mm; needle bar stroke: 35 mm; needle system: DPx5; needle hole diameter: 20-28 mm; tissue density: over 250 mg / mm³; fabric bag height: up to 8 mm. On sewing machines of this subclass, thin leather, leatherette, densely knitted fabrics, woven and non-woven materials, such as denim, jersey, Brisbane, pique, footer, fleece, gabardine, diagonal, cashmere, boucle, tweed, drape, tarpaulin, are most often sewn, felt, oxford, Cordura, etc.
To expand the range of sewn fabrics, for models of both subclasses, it is possible to use change-over sets in both directions. Such kits consist of a needle plate, presser foot, and gear rack. The use of readjustment kits, of course, does not solve all the problems, however, it allows you to situationally obtain a more acceptable stitch quality on materials that are beyond the range of this subclass of machines. Therefore, when buying a straight line, you must first focus on those materials that you have the most in the assortment and, accordingly, choose a subclass of the machine.