What is a bobbin on a sewing machine?

A bobbin is a small spool that holds the bottom thread in a sewing machine. It sits in a bobbin case, which is typically located beneath the sewing machine's needle plate. The thread from the bobbin is pulled up through the needle plate and interlocks with the upper thread to create a stitch.

Bobbin size and type can vary between different sewing machines, so it's important to use the correct bobbin for your machine. Bobbins are typically made of plastic or metal and can be either pre-wound or filled manually by the user.

A sewing machine typically has a thread tension dial that allows the user to adjust the tension of the upper and lower threads. Proper tension is important for creating even, smooth stitches and preventing thread knotting or breakage.

To ensure the bobbin works properly, it's important to keep it clean and free of lint or debris. A damaged or worn bobbin can also cause issues with stitching and should be replaced as needed.