Motor Grader


When we refer to civil works , many of the earthworks that are included in this activity are carried out so that the surface where they are going to work is uniform and flat , without any type of undulation or grooves. The motor grader is a machine that has been built for this purpose, this self-moving machine is used in large projects for construction of roads and buildings. In the market you can find different types of models which are classified depending on their weight and power, in addition to the specific characteristics that each one of them have.

What is the motor grader?

The motor grader is a machine used in civil engineering with the aim of leveling the ground by means of earth movements to avoid the existence of grooves , holes or undulations that could affect the construction.

  • What is a motor grader for?
  • Characteristics
  • Story
  • Parts of a motor grader
  • How a motor grader works
  • Examples

What is a motor grader for?

The motor grader is a very functional machine when we refer to constructions, its main function is to level , mold or slope the earth materials that are in a certain place. Carries out leveling of land , is capable of profiling slopes in landfills and dumps and roadsides of roads, with the degree of tilt is needed, this because the central blade can be tilted to the right or left, depending on the need.


This important civil engineering machine is used in the construction of highways , roads , leveling of agricultural land, construction and cleaning of canals and clearing landslides in cases of emergency due to extreme weather conditions.


The main characteristics of a motor grader are the following:

  • They generally have a motor with a power rating of approximately 120 to 200 hp.
  • The blade with which it works has a working width of 3.8 m.
  • When you have rear scarifying teeth , they can reach a working depth of 20 cm and even more.
  • Its  normal working speed  is 3.0 – 7.0 km / h.
  • It has an acoustic signal that indicates your reverse gear.
  • There are rigid and articulated motor graders .


The first motor grader according to the studies carried out was invented at the beginning of the decade of the 1900s.  The creation of this revolutionary earthwork machine produced a change in the way in which it was worked, since at that time, horses were the in charge of shooting to achieve the objectives. In 1928, the prestigious Caterpillar company emerged and entered the market with great and powerful innovations in its products, quickly reaching leadership .

In 1909, the motor grader was known by the name of ” Holt ” motor grader , then between 1973 and 1995 the machines were known as Series G , Series H between 1995 and 2006.

Parts of a motor grader

The parts or components of the motor grader are as follows:

  • Moldboard foot : it is the end that is closest to the front wheels of the machine.
  • Heel of the moldboard : it is the end that is closest to the wheels of the machine.
  • Rotation of the circle : it is the part of the machine that allows a 360 degree rotation of the circle to be made to adapt the angle of the blade to the type of material. The circle is supported at six points by means of three fixing plates and three adjustable guide shoes , for maximum circle support and better load distribution.
  • Frame : it is the chassis of the machine that supports the parts that carry a motor grader.
  • Front axle : these are the wheels at the front. In some machines they are connected to the chassis by means of a pivot and in others this connection is rigid.
  • Engine : runs on diesel and is located at the back of the machines.
  • Transmission system .
  • Cabin : place where the driver is located and is located in the central part of the machine.
  • Drawbar : it is a beam that is responsible for transmitting the traction effort of the chassis to the blade system.
  • Blade : is the blade of the machine in charge of making the cuts and being in contact with the ground.

How a motor grader works

These types of machines are self-propelled and have a central blade that is responsible for cutting or scraping the ground to achieve leveling , while performing this function they also accumulate the material and deposit it in a different place. The knife or blade that the machine has can be placed in a higher position so that the machine can be moved from one place to another, and then it is returned to the position it was in to be able to continue with the work.


Some examples of motor graders are as follows:

  • Caterpillar M-Series Motor Graders
  • Volvo G940 Motor Grader
  • Caterpillar 24H Motor Grader (World’s Largest)
  • CAT 140 K Motor Grader

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