A grader is a vehicle that is used to level or flatten a field or other piece of land. It has a large blade that is made of heat-treated steel. The blade may be placed in the front, at the rear or in between the front and the rear wheels of the vehicle. Graders are commonly used in: farming, road leveling, field and playground building, defense, construction, and mining, etc.
There are different types of graders such as motor graders and road graders. Graders are specified by: the engine horsepower, the number of cylinders, the vehicle weight, their maximum speed, the number of blades that can be fitted and the blade sizes, the angle of blade retraction, etc. Graders can have either rubber inflated wheels or tracks, similar to a tank. The range of a blade width on a grader is approximately of 2.5 to 3.1 meters and their engines generally range from about 125 to 275 horsepower.
The blades are angled in such a way that the debris flows smoothly. A small gap between the topsoil and the blade ensures that the right amount of material is retained and the rest is either pushed forward or flows to the sides. Multiple blades, one behind the other makes sure that the grading is refined.
Typical models of graders have three axles. The engine and the cab are located above the rear axles at one end of the vehicle and the third axle is positioned at the front end of the vehicle, with the blade usually located in between.
Graders are used typically in road surfacing operations such as asphalting. Generally, the concrete mix, asphalt or tar has to be leveled or graded. They are also commonly used in maintenance of unpaved roads and to prepare the base course to create a wide flat surface for the asphalt to be placed on. In addition, they are also used to set native soil foundation pads to finish grade before the construction of buildings. In the construction of housing developments and playgrounds, the soil is first excavated by bulldozers or scrapers and then leveled using graders.