The specific steps are as follows:

Step 1, preparing accessories of the buttonhole locking device;

Step 2, draw the distance between the two sides of the buttonhole on the material to be sewn, draw a straight line with a common pencil, and install a mold on the accessories of the buttonhole locking device;

Step 3: Adjust the buttonhole size (mm), install the attachment position of buttonhole locking device, fix the arm and foot of the attachment, and start sewing.

Jh8330a is a butterfly sewing machine. Butterfly sewing machine is an early sewing machine brand. Since 1970s, Butterfly brand sewing machines have sold well all over the country. It was one of the "three great things" of that era. 1927, the first domestic sewing machine in China was born here, named "Golden Lion". In 1946, the word "golden lion" was changed to "invincible", meaning "invincible hand all over the world". 1966, in order to unify the Chinese and English trademark names at home and abroad, Invincible Brand was renamed "Butterfly Brand" again, and the English trademark was "Butterfly". Since then, the trademark "Butterfly Brand" has continued to this day.