Butt hinges are a common type of hinge used in South Africa. Also known as a Mortise hinge, the butt hinge is most commonly used in pairs on doors. A butt hinge is constructed of two matching leaves of metal connected by a central pin and barrel system. One leaf of the butt hinge is mortised, or recessed, into the door while the other is attached to the jamb. When properly installed, the two leaves of a butt hinge should sit flush against each other, which allows the door to sit perfectly flush with the jamb.