How to repair a household sewing machine with poor thread bottom?

Take out the lock shell and loosen the bottom line slightly. If the bottom line is not good, adjust the top line slightly to solve the problem. If the top line is not good, follow the opposite adjustment method to completely solve it.

The bottom line of the household sewing machine repair is tight, not straight, and has a raised board. When using a sewing machine, the bottom line is not straight and tight, and the hour hand suddenly stops moving, causing the bottom line to become uneven. If the winding direction of the spindle is reversed and the exit angle is greater than 90 degrees, the thread will become too tight 2 or the shuttle thread is not clamped into the thread groove and is pressed by the shuttle skin 3. Or the adjusting screw of the shuttle leather is tightened too tightly How to repair the noise of a household sewing machine? Open the cover on the machine head to see the presser foot rod connected to the presser foot. Turn the needle rod to the lowest position, loosen one screw on the presser foot rod, and the presser foot will fall down. Fix it again, and that's it