The overlock device, in contrast to the sewing machine, implies the presence of three or four threads. To deal with all the threads and get an even stitch of good quality, you have to spend a lot of effort …
When you first get to know the overlock, you should pay great attention to its operating instructions, where you can find the refueling diagram. They also describe in great detail the purpose of all adjustments and their location. Many manufacturers quote recommended values to get quality stitches. If you could not read the instructions for some reason, then you need to be patient and start experimenting.
First you need to prepare the overlock, threads and material. Moreover, the threads should be of the same quality, but of different colors (this will make it easier to understand). For a start, you need to take a simple material (not knitwear, not too thin and not too dense). Coarse calico or something similar is best suited.
Further, after the correct threading, you need to set all the thread tension regulators to an average value, usually 3 or 4, and sew a small distance, while the stitching may not be ideal. You can compare it with the stitching on an already finished product, for example: T-shirt, T-shirt, etc.
Now let's start understanding the adjustments. Try twisting one of the thread tension adjusters (clockwise increases; counterclockwise decreases). Take a look at the resulting line. If you have increased the thread tension, then the thread should tighten the material more. If reduced, then, accordingly, the thread will lie more freely in the line (loop). For yourself, note which thread in the line this adjustment corresponds to. Return the tension to the previous (average) value and repeat the experiment on other regulators. Thus, sorting out all the tensioners in turn, you can determine the optimal settings.
In addition to adjusting the thread tension, the overlock has adjustments for stitch density, edge trim and differential feed. Density Adjustment - changes the amount of material advance in one shot. By adjusting the trimming edge, you can achieve a better fit of the threads to the trimmed edge. But the adjustment of the differential feed adjusts the advance of the material, while adjusting the assembly and stretching of the material. The average value of this adjustment is 1 (it is better to leave it at one until you figure out the rest of the settings). If you need to assemble the material, then the value is set to more than one. A value less than one (most often used on knitwear) is set in cases where the material needs to be stretched (to give a margin for stretching).
After the purpose of all the adjustments is clear and each of them has been tested in different versions, it will not be difficult to adjust the stitching in the same way as on the factory product.
