What's with the on-line and off-line of the household sewing machine?

The sewing machine thread is not tight because the shuttle skin is broken or the thread pressing screw is loose, so the thread cannot be clamped. Adjust the thread at any time according to the tightness of the thread, and the thread is not tight after final adjustment. It may be that the needle is not installed correctly, the upper and lower grooves on the needle are inconsistent with the direction of the thread, or the hole of the threading pressure plate has burrs, and the center of the shuttle bracket has burrs.

Check the needle. If it is loose or misplaced, correct it. Check whether the needle is installed in the wrong direction, especially the round handle needle. Check whether the needle bar moves upward due to loose screws. Check whether the crank screw of the lower shaft is loose, resulting in left-right dislocation or circumferential displacement of the lower shaft. Check whether the shuttle spring is broken. Check whether the shuttle cover screw is loose, causing the shuttle cover to move to the left. Check whether the gear hook at the lower end of the needle bar is loose or not.

? There are many ways to classify sewing machines, and it is common to distinguish them according to stitches and uses. The stitch of sewing machine can be divided into lock stitch and chain stitch. Lock stitch is the most common stitch, which consists of two stitches, intertwined like a rope, and its interweaving point is in the middle of sewing materials. From the cross section of the stitch, two stitches are like two locks, so it is called a lock stitch. This stitch is used to sew materials such as cotton, wool fabric or leather with small shrinkage, and the front and back shapes are the same, such as the dotted line. The stitch distribution is dense, and the sewing fastness is generally higher than that of manual sewing.