Ratchet screwdrivers

Ratchet screwdriver

— a screwdriver equipped with a ratchet mechanism (ratchet). The principle of operation of such a mechanism is that when the handle is rotated in one direction, the tip rotates with it, transferring force to the fasteners, and when rotated in the other direction, it remains in place. Thus, you can work with a screwdriver without intercepting the handle — just turn it back and forth, the tip will still turn in only one direction. To change the direction (for unscrewing or twisting), the corresponding switch is necessarily provided in the design. Often it also has a third position, in which the tip is completely blocked, and the tool works like a classic screwdriver.

At idle, the mechanism of such a tool emits a characteristic crackle, hence the name.