Drilling refers to the technique of making holes into items such as wood, stone or into the ground. Drilling and cutting dates back to the ancient times, 25000 years BC, by use of simple methods of rotation. Drilling methods were developed among the ancient people in Egypt, Asia and America (Moloney, 1995, P.146; McCveire, 1891). At about 1000 BC, a drilling rig made of bamboo wood and a percussive cable was proposed in the ancient China (Moor, 1977). The drilling rig was improved by Leonardo da Vinci’s to become more efficient. The drilling devices were hand powered and used water for lubrication and cooling purposes. Water was also used to remove the broken remains of the drilled hole.

During the ancient period, drilling a small hole required a lot of efforts and long hours. The primitive drilling methods used are the awl and the hand drill. The awl is a sharp stone or copper, attached to a piece of wood. While drilling, the awl was pressed against the object to be drilled and then rotated by hand. Since drilling into a hard surface such as stone was highly labor intensive, efforts to invent more efficient drilling machines became active. Therefore, efforts towards mechanization led to development of strap drills, bow drills and pump drills. Over the years, drilling and cutting has evolved greatly, from simple drill bits made of stone, bronze and iron in 3000 BC, to invention of a triple bow drill in 1450 BC. Currently, electric-powered drilling and cutting machines that are faster and more efficient are in use.

Advantages and disadvantages of drilling and cutting:

Advantages of drilling and cutting include facilitating access to water, gas and oil from deep in the earth. Drilling also simplifies the process of building and construction. Drilling is a fast process that is used to penetrate hard rock.

Disadvantages of drilling and cutting include risk of injury to personnel and high cost of implementation. Drilling process requires skilled personnel to operate.

Safety methods of drilling and cutting:

Percussion drilling involves lifting and dropping a heavy cutting tool which removes materials to form a hole. The drilling tool can be attached to a cable to facilitate its use. Hand auger drilling is most suitable for unconsolidated deposits.

Hand auger drilling is used by rotating the auger head into the ground to bore the hole. The auger head is then slowly removed to get rid of the excavated materials.

Sludging also known as reverse jetting is a drilling technique that uses a hollow drill pipe made of bamboo or steel. The drill pipe has teeth at the bottom that cuts the hole as it moved up and down. Water is then pumped down the borehole and out through the drill pipe to remove the debris.

Rotary-percussion drilling is the main technique used in regions with very hard rocks. The hard rock is first crushed to soften using a pneumatic hammer. The drilling machine is then driven into the rock at high speed using compressed air.

Examples:

Drilling cannot occur without cutting. Drilling machines use cutters to produce special holes. Examples of cutters used include countersinks and counterbores. Countersinks are cutting machines with special angles. They are used to counter sink angles for flat head screws. Counter bores are special cutting machines that use a pilot to guide the cutting process.

References

McCveire, J.E. (1891). A study of the primitive methods of drilling.- Report of National Museum, Washington, 9l, 623-756.

Moloney, N. (1995). Archaeology. Oxford University Press, 146.

Moor, W.D. (1977). Ingenuity sparks drilling history. Oiland Gas Journal, 35, 159-164, 175-177.