Pin and Knife Hinges

Semi-concealed pin and knife hinges, also known as half-mortise pin and knife hinges, are a type of hinge that is designed to be mounted on the surface of a door or frame, with only half of the hinge visible when the door is closed. These hinges are called "semi-concealed" because only half of the hinge is hidden, while the other half is visible. They are called "pin and knife" because they have a pin that connects the two leaves of the hinge, and a knife-like blade that fits into a corresponding groove in the other leaf.