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Raising is a
Raising is a metalworking
Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale ...
technique whereby sheet metal
Sheet metal is metal formed into thin, flat pieces, usually by an industrial process. Sheet metal is one of the fundamental forms used in metalworking, and it can be cut and bent into a variety of shapes.
Thicknesses can vary significantly; ex ...
is formed over a solid object by repeated "courses" of hammering and annealing. A sheet metal worker is often required to raise, or bump, the work into form from the flat metal by means of a raising hammer and raising block. The raising block is made from substance giving resistance to the blows.
A modern term is ''synclastic raising'', the dominant curves of the object being forged are at right angles and move in the same direction; as in a bowl. This results in a surface possessing elliptic geometry
Elliptic geometry is an example of a geometry in which Euclid's parallel postulate does not hold. Instead, as in spherical geometry, there are no parallel lines since any two lines must intersect. However, unlike in spherical geometry, two lines a ...
.
''Anticlastic raising'', on the other hand, refers to shaping an object where the dominant axes move in opposite directions; a familiar example of this is a potato crisp
A potato chip (North American English; often just chip) or crisp (British and Irish English) is a thin slice of potato that has been either deep fried, baked, or air fried until crunchy. They are commonly served as a snack, side dish, or appe ...
. This results in a surface possessing hyperbolic geometry
In mathematics, hyperbolic geometry (also called Lobachevskian geometry or Bolyai– Lobachevskian geometry) is a non-Euclidean geometry. The parallel postulate of Euclidean geometry is replaced with:
:For any given line ''R'' and point ''P'' ...
.
See also
*Planishing
Planishing (from the Latin ''planus'', "flat") is a metalworking technique that involves finishing the surface by finely shaping and smoothing sheet metal.
Process
This is done by hammering with a planishing panel hammer or slapper file against a ...
* Sinking (metalworking)
Sinking, also known as doming, dishing or dapping, is a metalworking technique whereby flat sheet metal is formed into a non-flat object by hammering it into a concave indentation. While sinking is a relatively fast method, it results in stretchin ...
References
Bibliography
*Finegold, Rupert and William Seitz. ''Silversmithing''. Krause; 1983. Metal forming {{metalworking-stub