Brusso ST-12 Knife Hinges
The ST-12 brass center pivot hinge is employed when a minimum of visible hardware is desired or when the door must swing free of its frame. It is mortised into the top and bottom of the door and frame; only the pivot is visible. The leaf measures 1-3/8" x 5/16" x 3/32". The hinge is sold in pairs and installation instructions are available.