Slotted angle (also sometimes referred to as slotted angle iron) is a system of reusable metal strips used to construct

shelving A shelf ( : shelves) is a flat, horizontal plane used for items that are displayed or stored in a home, business, store, or elsewhere. It is raised off the floor and often anchored to a wall, supported on its shorter length sides by brackets ...

, frames, work benches, equipment stands and other structures. The name derives, first, from the use of elongated slots punched into the metal at uniform intervals to enable assembly of structures fixed with nuts and bolts, and second, from the longitudinal folding of the metal strips to form a right angle.

Invention

Prototype slotted angle strips were developed by

London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...

-based

engineer Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the l ...

Demetrius Comino Demetrius Comino OBE (4 September 1902 – 27 September 1988)Darbyshire, Anthony, and Duckworth, Eric (2011), ''Demetrius Comino: A life and legacy of achievement'', Comino Foundation. – (accessed: 22 February 2012) was an Australian engineer, ...

in the late 1930s,Darbyshire, Anthony, and Duckworth, Eric (2011), ''Demetrius Comino: A life and legacy of achievement'', Comino Foundation. as he sought alternatives to conventional wooden shelving in his printing works. Comino owned an engineering business,

Dexion Dexion is a company name and brand particularly associated with the development of the "Dexion" slotted angle steel strip construction system, widely used since the 1950s for domestic and commercial shelving, storage racking, exhibition stands ...

Ltd, which began production in 1947 and the steel slotted angle strips eventually became known as Dexion. The prior existence of

Meccano Meccano is a brand of scale model, model construction system created in 1898 by Frank Hornby in Liverpool, England. The system consists of reusable metal strips, plates, Structural steel#Common structural shapes, angle girders, wheels, axles and ...

prevented a generic patentProfile: Demetrius Comino "The secret is: think about first principles", ''New Scientist'', 25 July 1952, pp.20-21. so Dexion patents were restricted to particular slot and hole configurations, and, seeking to emulate Dexion's success, other UK and European companies began offering different sizes, hole patterns and metal strip thicknesses.

Production

Steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...

remains the most commonly used slotted angle material, although

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 ...

alternatives are also available.Aluminum Angle Iron Making Process - http://www.slottedrack.in (accessed: 22 July 2017) The product is generally manufactured from

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 ...

using

machine press A forming press, commonly shortened to press, is a machine tool that changes the shape of a work-piece by the application of pressure. The operator of a forming press is known as a press-tool setter, often shortened to tool-setter. Presses ...

es to form the angle and to punch holes through the metal. The strips are normally produced in a variety of standard lengths, and steel versions are often painted or

galvanized Galvanization or galvanizing ( also spelled galvanisation or galvanising) is the process of applying a protective zinc coating to steel or iron, to prevent rusting. The most common method is hot-dip galvanizing, in which the parts are submerged ...

to protect them from rust.

Construction

To construct items from slotted angle, items can be cut to size (some versions are marked to show the optimum points at which to cut the metal) using special slotted angle cutters or

shear Shear may refer to: Textile production *Animal shearing, the collection of wool from various species **Sheep shearing *The removal of nap during wool cloth production Science and technology Engineering *Shear strength (soil), the shear strength ...

s, and then fixed with nuts and bolts. Tension plates and other metal strips are also available to add strength to the finished structure.

References

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