A rolling mill is a tool comprised of a pair of hardened steel rollers that turn together on gears within a frame. Its purpose is to transform ingots or rods into wire or sheet. These rollers are adjustable to provide varying degrees of compression on the material being fed between them.
The rolling mill was invented in the late Middle Ages and replaced the classical hammering of gold into sheets. Because of the high malleability of precious metal extremely thin sheets or wire can be produced this way which can then function as the building blocks of a jewelry item. Sheet can be further worked by chasing, repoussé, striking and stamping or be decorated by soldering on filigree or granulation.