Number of stitches
The number of stitches that a sewing machine can sew. The larger this number, the more extensive the capabilities of this model, the wider the choice the user has; however, it wouldn’t hurt to clarify the specific range of supported stitches separately.
The fewest options - mostly up to 25 - are provided in electromechanical machines, as well as specialized devices such as overlockers and carpet lockers (see “Type”). In computer-controlled devices, the number of lines can be in the dozens, and some also allow you to download additional options from the computer.
Max. stitch width
The maximum stitch width provided by a sewing machine.
Most modern sewing machines are capable of working not only with the simplest longitudinal seam (when punctures with a needle occur strictly one after another), but also with seams that cover a certain width - for example, zigzag and various decorative ones. And in overlockers, such opportunities are generally available by definition.
The larger the maximum stitch width, the correspondingly wider the machine’s ability to work with specific types of seams (all other things being equal). An indicator of up to 5 mm is typical mainly for entry-level devices, 5 - 7 mm - average, 7 mm and more - advanced.
Sewing speed
The maximum sewing speed provided by the sewing machine. In the vast majority of models, this parameter can be adjusted, so that, if necessary, you can sew at a lower speed.
The more stitches per minute the machine makes, the higher its productivity, and the better it is suitable for large volumes of work. At the same time, note that high speed has a corresponding effect on price and power consumption, and it is not always required. Detailed recommendations on choosing the optimal speed for certain types of work can be found in special sources.
Adjustments
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Presser foot pressure adjustment. The ability to change the degree of pressure of the foot on the fabric, adjusting it to the thickness of the material: for thin fabrics (chiffon, knitwear), the pressure should be small, for thick ones — on the contrary.
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Thread tension regulator. A device that allows you to adjust the degree of tension of the upper thread. A mismatch in tension between the top and bottom threads causes one of the threads to pull the other and the seam deteriorates. To avoid this phenomenon, this function is provided. Note that tension adjustment is also possible for the lower thread — it is carried out through the shuttle (all shuttles have this option). But for this, it is necessary to remove the bobbin case or even the entire shuttle. The top regulator is located directly on the body of the machine, and it is much easier to use it.
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Puncture force stabilizer. A device that provides a stable puncture force regardless of the engine speed. A feature of the mechanics of electric motors is that without special adjustment, the puncture force decreases markedly with an increase in speed. This function allows you to maintain approximately the same level over the entire speed range, which has a positive effect on the quality of work.
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Feed shutdown. Possibility to turn off the bottom feed of the
...machine. This feature is indispensable for work in which the fabric needs to be shifted manually — for example, embroidering along a complex contour on a typewriter without an embroidery unit, sewing on buttons, etc.
— Speed control. The ability to set a speed limit for the machine. Thanks to this function, you can not be afraid to "squeeze" the pedal — even with strong pressure, the machine will work at a given speed, and no faster. This feature is useful, in particular, in jobs where you need to carefully control the process.
— Knee lever. A device that allows you to raise the presser foot and lower the lower feed dog with a knee movement without removing your hands from the fabric. Such a device is useful for quilting and some types of embroidery.
