Archaeologists discovered a Neolithic grave yard in Mehrgarh, Pakistan dating from the time of the Harappans, around 7,500–9,000 years ago, containing 9 adult bodies with a total of 11 teeth that had been drilled. Mainly used to create fire, bow-drills were also used in ancient woodwork, stonework, and dentistry. It was discovered that tying a cord around a stick, and then attaching the ends of the string to the ends of a stick (a bow), allowed a user to drill quicker and more efficiently. Bow drill (strap-drills) are the first machine drills, as they convert a back and forth motion to a rotary motion, and they can be traced back to around 10,000 years ago.
