Used extensively in bookbinding, a board shear is a big, hand-operated machine for reducing board or paper. Like scissors, a board shear uses two blades to use shear stress exceeding the paper's shear energy so as to chop. The stationary blade varieties the edge of the cutting desk, with the shifting blade mounted on a reducing arm. Originally often called a desk gauge shear because its gauge allowed the chopping of persistently-sized supplies, the board shear resembles a larger model of the paper cutters generally found in places of work. The earliest known reference to a board shear comes from an 1842 complement to Penny Magazine, titled A Day at a Bookbinder's, which included a drawing of a board shear with a lot of the major developments already present. Middleton, Bernard (1996). A History of English Craft Bookbinding Technique. Oak Knoll Press & The British Library. Harrison, Gary. "Board Shear". This text about making art out of books, the arts associated to bookbinding, or the design of mass-produced books is a stub. You may help Wikipedia by expanding it.

Viscosity is a measure of a fluid's rate-dependent resistance to a change in shape or to movement of its neighboring parts relative to each other. For liquids, it corresponds to the informal idea of thickness