Written by Erin Hammeke, Special Collections Conservator
Some of my favorite bindings in the ledger collection are the mechanical bindings. These bindings are feats of engineering, with metal components and moving parts! They come in a variety of shapes, sizes, and styles.
This item from the Erwin Mills collection is notable for its size and mechanics. The text is laced through the side and then the yellow straps serve to hold the covers on. A tensioning system, built into the covers, allows the distance between the boards to expand or contract as additional text paper is added or removed. So neat! 
This ledger from the Cannon Mill collection has a metal spine piece, as well as corduroy sides – an endearing and favorite covering in 19-20th century ledgers. Many of the mechanical and account book bindings were trademarked and have manufacturing information pasted to the front pastedown, as shown in this item.
