A buttonholer is an attachment for a sewing machine which automates the side-to-side and forwards-and-backwards motions involved in sewing a buttonhole. ... The buttonholer's adaptor attaches to the machine's presser bar, replacing the presser foot.

What is the benefit of using a buttonhole attachment?

A built-in one-step buttonhole feature is great because the foot measures the actual size of your button each time is sews a buttonhole. This means that every buttonhole you stitch will look just like the last, providing you with consistent, professional results – no matter how many you sew!

What is an overcasting foot?

The overcast foot is also known as an over-edge or over locker foot. ... The overcast foot works by having a bar in the centre which wraps the thread around the edge of the fabric as you stitch, whilst preventing the fabric from curling. Clip the foot onto your sewing machine with the bar attachment.