Used extensively in

bookbinding Bookbinding is the process of physically assembling a book of codex format from an ordered stack of ''signatures'', sheets of paper folded together into sections that are bound, along one edge, with a thick needle and strong thread. Cheaper, b ...

, a board shear is a large, hand-operated machine for cutting board or paper. Like

scissors Scissors are hand-operated shearing tools. A pair of scissors consists of a pair of metal blades pivoted so that the sharpened edges slide against each other when the handles (bows) opposite to the pivot are closed. Scissors are used for cutti ...

, a board shear uses two blades to apply

shear stress Shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. ''Normal stress'', on the ot ...

exceeding the paper's

shear strength In engineering, shear strength is the strength of a material or component against the type of yield or structural failure when the material or component fails in shear. A shear load is a force that tends to produce a sliding failure on a materia ...

in order to cut. The stationary blade forms the edge of the cutting table, with the moving blade mounted on a cutting arm. Originally known as a table gauge shear because its gauge allowed the cutting of consistently-sized materials, the board shear resembles a larger version of the paper cutters commonly found in offices. The earliest known reference to a board shear comes from an 1842 supplement to ''

Penny Magazine ''The Penny Magazine'' was an illustrated British magazine aimed at the working class, published every Saturday from 31 March 1832 to 31 October 1845. Charles Knight created it for the Society for the Diffusion of Useful Knowledge in response to ...

'', titled ''A Day at a Bookbinder's'', which included a drawing of a board shear with many of the major developments already present. An 1854 article on the history of bookbinding from ''The Bookbinder's Trade Circular'' describes early board shears, and places their development in "about 1836"; credit for the invention is ascribed to Warren De La Rue in the ''Reports of the Juries'' from the

Great Exhibition of 1851 The Great Exhibition of the Works of Industry of All Nations, also known as the Great Exhibition or the Crystal Palace Exhibition (in reference to the temporary structure in which it was held), was an international exhibition which took pl ...

. Many modifications of the basic design were made in the 19th century, with changes such as rack-and-pinion adjustment for the outer gauge and improved clamp bars.Robinson, J.T. U.S. Patent 225871, 1880.

References

Book arts Bookbinding {{book-art-stub

See also

References