Engine turning, also known as jewelling, is a fine

geometric Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is ca ...

pattern turned onto

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...

as a finish.

Aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

is often the metal chosen to

inscribe {{unreferenced, date=August 2012 An inscribed triangle of a circle In geometry, an inscribed planar shape or solid is one that is enclosed by and "fits snugly" inside another geometric shape or solid. To say that "figure F is inscribed in figur ...

, but any appropriate surface can be finely

machined Machining is a process in which a material (often metal) is cut to a desired final shape and size by a controlled material-removal process. The processes that have this common theme are collectively called subtractive manufacturing, which utilizes ...

to produce intricate repetitive

pattern A pattern is a regularity in the world, in human-made design, or in abstract ideas. As such, the elements of a pattern repeat in a predictable manner. A geometric pattern is a kind of pattern formed of geometric shapes and typically repeated l ...

s that offer reflective interest and fine detail.

Uses

Aircraft

Perlée {{Unreferenced, date=April 2020 Perlée and perlage are French words for ''pearl pattern'', a decorative metallic finish consisting of a pattern of small circles (''pearls'') applied to a surface by grinding. It is mostly used in the automotive an ...

''-style engine turning was used on the sheetmetal panels of the engine cowling (nose) of

Charles Lindbergh Charles Augustus Lindbergh (February 4, 1902 – August 26, 1974) was an American aviator, military officer, author, inventor, and activist. On May 20–21, 1927, Lindbergh made the first nonstop flight from New York City to Paris, a distance o ...

's aircraft, the ''

Spirit of St. Louis The ''Spirit of St. Louis'' (formally the Ryan NYP, registration: N-X-211) is the custom-built, single-engine, single-seat, high-wing monoplane that was flown by Charles Lindbergh on May 20–21, 1927, on the first solo nonstop transatlant ...

''. The sheet metal parts of the World War I

Fokker Eindecker The Fokker ''Eindecker'' fighters were a series of German World War I monoplane single-seat fighter aircraft designed by Dutch engineer Anthony Fokker.Boyne 1988 Developed in April 1915, the first ''Eindecker'' ("Monoplane") was the first purpose- ...

fighter aircraft series, especially around the engine cowl and associated sheetmetal, are noted for having a "dragged" form of engine turning entirely covering them. The tool creating the "swirls" was repeatedly moved along a short irregular path each time while pressed against the metal, to create the intricate appearance that was characteristic of the aircraft's sheet-metal parts. It is partly surmised to have been a mechanical method to "clad" a

duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age-hardenable aluminium alloys. The term is a combination of '' Dürener'' and ''aluminium''. Its use as a tra ...

-alloy sheet-metal panel with a layer of pure aluminum, for corrosion protection.

Automobiles

In the 1920s and 1930s, automobile parts such as

valve cover Rocker covers are covers that are bolted on over rocker arms in an internal combustion engine. They are called valve covers in the United States, Canada, and in situations where Rocker Arms are not present, such as some Overhead Cam, and most Du ...

s, which are right on top of the engine, were also engine-turned. Similarly,

dashboard For business applications, see Dashboard (business). A dashboard (also called dash, instrument panel (IP), or fascia) is a control panel set within the central console of a vehicle or small aircraft. Usually located directly ahead of the driver ...

s or the instrument panel of the same were often engine-turned. Customizers also would similarly decorate their vehicles with engine-turned panels.

Documents

Engravings produced by engine turning are often incorporated into the design of

bank note A banknote—also called a bill (North American English), paper money, or simply a note—is a type of negotiable promissory note, made by a bank or other licensed authority, payable to the bearer on demand. Banknotes were originally issued ...

s, and other high-value documents, to make

counterfeit To counterfeit means to imitate something authentic, with the intent to steal, destroy, or replace the original, for use in illegal transactions, or otherwise to deceive individuals into believing that the fake is of equal or greater value tha ...

ing difficult. The resulting graphics are called

guilloché Guilloché (; or guilloche) is a decorative technique in which a very precise, intricate and repetitive pattern is mechanically engraved into an underlying material via engine turning, which uses a machine of the same name, also called a r ...

Firearms

Engine Turning is also used on various firearm components to prevent corrosion by holding traces of oil and lubricants on the surface, in turn to a polished surface resulting in a smooth operation.

References

External links

Engine Turning on YouTube
Visual motifs Corrosion prevention {{Tech-stub