Early humans needed fire to keep themselves warm and to cook with. In time, they learned to carry fire with them, but when they had to start a new fire, they found a dry stick and flat piece of wood to use as a drill and hearth.
First, someone dug a small hole into the hearth and placed one end of the stick, or drill, in it. The person starting the fire twirled the stick in the hole until it produced a spark, then moved the tiny flame to dry tinder.
Another method aboriginals used was the fire saw. This involved running a hardwood stick across a notched softwood stick.
The friction caused by rubbing the two pieces of wood together created heat which ignited the sawdust.