The hinge required for any job depends on the design and size of the door that you want to hang. It's best to know the parts of a hinge before making your purchase. A hinge consists of the leaves, knuckles, pin, tips and bearings. The leaves are the flat components with screw holes that fasten to the door and jamb. The knuckle is the cylinder that holds the leaves to the pin. A hinge can have from two to five knuckles depending on the size of the door. The tips project from the top and bottom of the hinge to keep the pin from coming out of the knuckle. Bearings are important in heavy-duty hinges because they lubricate and reduce friction on heavy-duty knuckles.
Mortise hinge leaves are cut into the door and jamb so that they butt together. A full-mortise hinge is cut into both sides; a half-mortise hinge is cut into the door, the other leaf is surface-mounted.
The proper cabinet hinge is chosen depending on how the door is installed.