Pump drill

[1] It consists of: the drill shaft, a narrow board with a hole through the center, a weight (usually a heavy disc) acting as a flywheel, and a length of cord.

[citation needed] The end of the shaft usually has a slot or hole that can hold a hard bit that does the actual drilling, either by abrasion or by cutting.

[citation needed] To use, the shaft is first turned by hand so that the cord wraps around the top part, as much as possible, and the board is as the highest position.

A smooth downward pressure is exerted on the board, causing the shaft to rapidly spin.

The weight then keeps the shaft spinning so that the cord wind again around it, in the opposite sense, pulling the board up to the starting position, much like a yo-yo or button whirligig.