File (tool)
Most are hand tools, made of a case hardened steel bar of rectangular, square, triangular, or round cross-section, with one or more surfaces cut with sharp, generally parallel teeth.
[1] A rasp is a form of file with distinct, individually cut teeth used for coarsely removing large amounts of material.
For example, in the 13th century, ornamental iron work at Paris was done skillfully with the aid of files, but the process was a secret known only to a master craftsman.
[4] The Disston authors state, "It was not until the fourteenth century, however, that those who practiced art in ironwork began to use other tools, besides heat and the hammer, regularly.
"[4] This statement could mislead in the sense that stoning (with sandstone) and lapping (with wood, sand, and water) have never been rare activities among humans, or especially smiths.
The Disston authors mention Nuremberg, Sheffield, and Remscheid (they use the Reimscheid spelling) as leading centers of production for files as well as tools in general.
The activity in Remscheid reflects the metalworking spirit of the Rhine-Ruhr region in general (including Essen, Düsseldorf, and Cologne) rather than representing a single village of geniuses in isolation.
(Considering the Disston authors' mention of the blacksmith guilds of 13th-century Florence and 15th-century England, coupled with their mention of Nuremberg, Sheffield, and Remscheid, the region that sweeps from Florence through Nuremberg, the Rhine-Ruhr, the Netherlands, and up to Sheffield, can be compared to the modern economics notation of the Blue Banana.)
Prior to the industrialization of machining and the development of interchangeable parts during the 19th century, filing was much more important in the construction of mechanisms.
In today's manufacturing environment, milling and grinding have generally replaced this type of work, and filing (when it occurs at all) usually tends to be for deburring only.
Skillful filing to shape and size is still a part of diemaking, moldmaking, toolmaking, etc., but even in those fields, the goal is usually to avoid handwork when possible.
The cross-section of a file can be flat, round, half-round, triangular, square, knife edge or of a more specialized shape.
[2] A "tang" is a protrusion at the heel, tapered, parallel sided, or conical, for gripping, inserting in a handle, or mounting in a chuck.
These may also be called diamond laps, as the "teeth" are not regular projections, as in a file, but particles, usually shaped and located randomly and held in place by a softer (any other) material.
Filing machines are rarely seen in modern production environments, but may be found in older toolrooms or diemaking shops as an aid in the manufacture of specialist tooling.
Using a combination of strokes, and progressively finer files, a skilled operator can attain a surface that is perfectly flat and near flawless finish.
