A butt hinge is also known as a mortise hinge is one of the most popular and widely used hinges. A butt hinge consists of two rectangular metal plates or leaves joined by a central pin or rod that allows the leaves to rotate. One leaf is recessed into the edge of the door or frame and the other is mounted into the surface of the adjacent frame or door. Butt hinges are both versatile and reliable and come in a wide range of sizes and materials to suit different door types including interior doors, exterior doors and cabinets.