The chuck is the part of the impact driver that holds the screwdriver or drill bits. When the speed control trigger is pulled, the chuck will rotate in order to drive in screws or drill holes.
There are several different types of chuck found on cordless tools. The type found on cordless impact drivers is called a ‘quick-release’ or ‘quick-change’ chuck. These chucks are named so because, compared with 3-jawed chucks, it takes less time to insert or remove bits.
3-jawed chucks must be turned clockwise or anti-clockwise by hand or using a key to open or close the jaws and change bits. Cordless impact driver chucks, on the other hand, are simply pulled back or pushed forward to insert or remove bits, making the whole process a lot quicker.
How does the chuck work?
Most quick-release chucks consist of a metal bit holder surrounded by a spring-loaded outer sleeve. The bit holder, as the name suggests, is where the screwdriver or drill bit is inserted. At the bottom of the bit holder is a powerful magnet which touches the base of the bit, holding it in place. As well as a magnet, there is also a ball-bearing (some models have two) inside the chuck, which engages with the side of the screwdriver or drill bit, also holding it in place.
The spring-loaded outer sleeve of the chuck controls the position of the ball bearing. On some models, pushing the sleeve forward, retracts the ball bearing from the screwdriver or drill bit, allowing you to remove it.
On other models, this is done by pulling the sleeve back.