Engine turning

Not to be confused with swarf.

A Fokker E.II of late 1915, with the "dragged" engine turning on the engine cowl and associated sheetmetal.

Charles Lindbergh with his famous aircraft, the Spirit of St. Louis. The texture alongside his head is engine turning.

Engine turning refers to a fine geometric pattern that can be inscribed onto metal as a finish. Aluminium is often the metal chosen but any metal can be finely machined to produce intricate repetitive patterns that offer reflective interest and fine detail.

A 1940 Buick Super Convertible Coupe with a dashboard engine-turned by the owner.

Perhaps the most recognizable example of engine turning is the engine cowling (nose) of Charles Lindbergh's aircraft, the Spirit of St. Louis. In the 1920s and 1930s, automobile parts such as valve covers, which are right on top of the engine, were also engine-turned. Similarly, dashboards or the instrument panel of the same were often engine-turned. Customizers also would decorate their vehicles with engine-turned panels similarly. Recently, one firm engine-turns the faces of its automobile instruments for customizers who don't want to have to turn a panel themselves.

Engravings produced by engine turning are often incorporated into the design of bank notes and other high value documents to make production of forged copies difficult. The resulting graphics are called guillochés.

The sheet metal parts of the World War I Fokker Eindecker 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, and is partly surmised to have been a mechanical method to "clad" a duralumin sheet metal panel with pure aluminum with a disc of pure aluminum in the tool, for corrosion protection.

See also

• Perlée
• Guilloché
• Rose engine lathe