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Twist drills, with their helical cutting edges, became the standard for 75mm drill bits in the 1960s. These drills cut by shearing the material and ejecting it through the flutes, resulting in cleaner holes with less material buildup. The development of twist drills also led to the refinement of drill bit geometry, including the addition of secondary cutting edges and better chip evacuation channels The development of twist drills also led to the refinement of drill bit geometry, including the addition of secondary cutting edges and better chip evacuation channels The development of twist drills also led to the refinement of drill bit geometry, including the addition of secondary cutting edges and better chip evacuation channels The development of twist drills also led to the refinement of drill bit geometry, including the addition of secondary cutting edges and better chip evacuation channels75mm drill bit.

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The drilling process itself involves a technique known as 'circulation.' A drilling fluid, commonly referred to as 'mud,' is continuously pumped down the drill string, through the bit, and back up the annulus between the drill string and the walls of the hole. This fluid serves multiple purposes it cools and lubricates the bit, carries cuttings to the surface, stabilizes the borehole, and provides hydrostatic pressure to prevent underground fluids from entering.

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