Grader

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CAT G12 grader.

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

1918 grader.

CAT 143h plowing snow in Ouray, Colorado.

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A grader, also commonly referred to as a road grader, a blade, a maintainer or a motor grader, is an engineering vehicle with a large 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.

In civil engineering, the grader's purpose is to "finish grade" (refine, set precisely) the "rough grading" performed by heavier 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 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 Canada and places in the United States, graders are often used in municipal/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 Inc., or Mikrofyn [www.mikrofyn.com] for precise grade control and (potentially) "stakeless" construction.

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

[edit] 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.