Buttonhole
Definition
A buttonhole is a reinforced slit in a garment that a button passes through, usually sewn on a machine as two dense zigzag columns joined by bar tacks.
Most sewing machines make buttonholes automatically. A one-step buttonhole foot holds the button in a slot at the back, measures it and sews both columns, called beads, and the bar tacks at each end in a single sequence. Older machines use four steps selected by hand.
Getting the size right: the opening must be about the button's diameter plus its thickness. For a flat 1 cm (3/8 in) button, that is roughly 1.2 to 1.3 cm (1/2 in); domed or thick buttons need more. Always sew a test on a scrap with the same layers and interfacing.
Placement rules:
- Vertical buttonholes on plackets and shirt fronts, where the button stays centered.
- Horizontal buttonholes on waistbands and cuffs, where the strain pulls sideways. They start about 3 mm (1/8 in) beyond the button's center line, toward the edge.
- Even spacing, with one button at bust level on blouses to prevent gaping. The button spacing calculator works out the positions.
Interface the area behind buttonholes, and open them with a seam ripper, with a pin across each end as a stop, or with a buttonhole chisel. More in how to sew buttonholes and buttons.