คำถามที่พบบ่อย และการแก้ปัญหาเบื้องต้น

The lower thread could be breaking due to several reasons.
 

• Check to see if the lower thread be tangled.

One Point Advice   When thread got tangled

• The bobbin could be threaded improperly in the shuttle hook.
  Rethread the bobbin in the shuttle hook.

Please refer to "Installing a bobbin" of "Preparation" category.