grader

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Caterpillar 12G grader.

Modern grader in use by the U.S. military.

1918 grader.

Caterpillar 143H grader plowing snow in Ouray, Colorado.

A grader, also commonly referred to as a road grader, a blade, a maintainer, or a motor grader, is a construction machine with a long blade used to create a flat surface. Typical models have three axles, with the engine and cab situated above the rear axles at one end of the vehicle and a third axle at the front end of the vehicle, with the blade in between. On certain countries, for example in Finland, almost every grader is equipped with second blade that is placed on front of the front axle. Some hard hats refer to this machine as "the blade".

In civil engineering, the grader's purpose is to "finish grade" (refine, set precisely) the "rough grading" performed by heavy equipment or engineering vehicles such as scrapers and bulldozers.

Graders can produce inclined surfaces and surfaces with cambered cross-sections for roads. In some countries they are used to produce drainage ditches with shallow V-shaped cross-sections on either side of highways.

Graders are commonly used in the construction and maintenance of dirt roads and gravel roads. In the construction of paved roads they are used to prepare the base course to create a wide flat surface for the asphalt to be placed on. Graders are also used to set native soil foundation pads to finish grade prior to the construction of large buildings.

In some locales such as Northern Europe, Canada, and places in the United States, graders are often used in municipal and residential snow removal. In scrubland and grassland areas of Australia and Africa, graders are often an essential piece of equipment on ranches, large farms, and plantations to make dirt tracks where the absence of rocks and trees means bulldozers are not required. A more recent innovation is the outfitting of graders with GPS technology, such as manufactured by Topcon Positioning Systems, Inc., Trimble Navigation, Leica Geosystems or Mikrofyn for precise grade control and (potentially) "stakeless" construction.

Graders are also used for underground mining.

Capacities range from a blade width of 2.50 to 7.30 m and engines from 93–373 kW (125–500 hp).

Education

The National Association of Heavy Equipment Training Schools (NAHETS), established 2002, uses grader training schools and curriculum as a method to test and train users in the ability of grader use.

Some grader-producing companies

• John Deere
• Caterpillar Inc.
• Case
• Grove
• Komatsu
• New Holland
• Terex
• Volvo Construction Equipment
• Mitsubishi Heavy Industries
• Galion
• Champion Motor Graders
• Veekmas

See also

Wikimedia Commons has media related to: Grader

• National Association of Heavy Equipment Training Schools—U.S. educational organization
• King road drag
• A Road-Scraper That Cuts Through Snow, Popular Science monthly, February 1919, page 26, Scanned by Google Books: http://books.google.com/books?id=7igDAAAAMBAJ&pg=PA26
• Veekmas, maker of underground and common graders. Has also pictures of front blade arrangement. http://www.veekmas.com