How to distinguish the bottom line from the sewing machine.
Very simple, the above called the face line, the following is called the bottom line. The bobbin case is the bottom line, the needle that is the upper thread.
The bottom line is too loose, that is, you sew the fabric, the front line of the bottom line or the bottom line exposed fabric, the bottom line to send the opposite line is too loose, that is, in the bottom of the fabric ring or exposed cloth.
The upper part of the fabric line for the upper thread, the following straight line in the upper layer exposed coil, indicating that the upper thread is too tight or the bottom line is too loose, the bottom line to the upper fabric to the.
