H Hinges - Shaped like an H and used on flush mounted doors. Small H hinges (3" to 4") tend to be used for cabinets hinges, while larger hinges (6" to 7") are for passage doors or closet doors.

 

A hinge is a type of bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation (the geometrical axis of the hinge). Hinges may be made of flexible material or of moving components. In biology, many joints function as hinges. They are also known as shangles in old tudorian English (the large hinges on doors). Hinge-like structures are employed in many types of movable bridges.