I made a cord drill and then upgraded it to a pump drill. A cord drill is basically a spindle with a fly wheel attached so it looks like a spinning top. the middle of a piece of cord is then put into a notch at the top of the spindle. The ends of the cord are then wrapped around the spindle and then pulled quickly outwards causing the drill to spin.
source/image(PrtSc): Primitive Technology
The momentum of the fly wheel causes the cord to wrap back around the spindle in the other direction. When it stops the cords are pulled outwards again and the drill spins in the other direction./Primitive Technology
I made the first one with a stone flywheel then made fire with it in the same way I make fire with fire sticks. Then I made and fired some clay fly wheels, made another drill with one of the fly wheels and fitted a stone drill bit to the end. This one I use for drilling holes in wood.
I used the new drill to make a hole in a piece of wood. I then put the spindle of the original cord drill through the hole in the wood, tied the ends of the cord onto the piece of wood and it became a pump drill. The main purpose I’d use these tool for is drilling holes rather than fire making. It was reasonably good but the stone bits I made could be improved and their attachment to the shaft also needs some thought.via/read more: Primitive Technology