Indiana University Libraries Book Repair Manual
Edge Boards
These are placed between books in a standing press. They are wooden boards with a strip of metal on one edge, which protrudes about ΒΌ" beyond both flat surfaces of the board (resulting in a T-shaped cross-section). These edges fit into the hinge of the book and help to create a well-defined gutter between the back (spine) edges of the boards and the shoulders of the text block.
Flat Boards
These are used along with edge boards in the standing press. They are placed on the absolute bottom and top of the stack of work, to allow clearance, preventing the metal edges of the edge boards from being bent by the press as it is tightened down. They are also used under weight for flattening materials.