Brother NC21SE Operation Manual page 110

SEWING THE STITCHES
One-step buttonholes are sewn from the front of the presser foot to the back, as shown below.
a Reinforcement stitching
a a a a
Select a buttonhole stitch, and attach
buttonhole foot "A".
b b b b
Mark the position and length of the
buttonhole on the fabric.
Memo
The maximum buttonhole length is about
28 mm (approx. 1-1/16 inches) (diameter +
thickness of the button).
98
a
a
c c c c
Pull out the button holder plate on the
presser foot, and insert the button that will
be put through the buttonhole. Then tighten
the button holder plate around the button.
a Button holder plate
Memo
The size of the buttonhole is decided by the
button holder plate holding the button.
a
a
a