An auger is a type of drill; a hydraulic auger is a drill that uses hydraulic pressure for power. It can be a relatively small and light hand tool or a large piece of construction equipment. The hydraulic auger was first introduced in 1953 as a hydraulic drill rig. Since then, the technology has become increasingly sophisticated and has found a multitude of applications.
A hand-held hydraulic auger is used to drill holes in materials such as wood. Earth augers are used for drilling holes for fence posts and signs. Other hydraulic augers are capable of drilling into hard substances, such as concrete, frozen ground, and solid rock. These large drilling rigs may be mounted on trucks or may have to be secured to the ground and are used to drill deep boreholes.
The hydraulic auger is a type of machine that makes use of Pascal's Principle. This is the principle outlined by the scientist Blaise Pascal that states that pressure is transmitted everywhere undiminished in an enclosed static fluid. This allows a small piston moving a long way through an enclosed space with little force to move a large piston a short distance in a large space with great force.
This multiplication of force enables large amounts of mechanical work to be done by hydraulic machines. In the case of the hydraulic auger, the force is used to sink boreholes. The use of hydraulics allows not just a great deal of force to be applied but also permits variable drilling speed and for the direction of rotation to be reversed.
A hydraulic auger consists of a drive that provides the hydraulic power needed for drilling and the auger itself, which is the part that actually drills into the ground. The auger itself consists of a central tube, termed the barrel, with helical blades around it. These blades are known as the flighting. As it turns, the auger removes material from the hole and moves it up the helical flighting. The tip of the auger may be a replaceable part that bolts on to the end of the bit, thus allowing it to be removed when it becomes too worn.
Materials used to make auger heads typically need to be quite strong and have hard edges. A common combination is a hard carbon steel body with tungsten carbide edges for sharpness. These edges are sometimes called hard-facing, and such an auger may be called a hard blade.