The chuck is the part of the cordless impact driver that holds screwdriver and drill bits.
Most cordless impact drivers have a quick-release hexagonal chuck, which can accept screwdriver or drill bits with hexagonal shanks, provided they are of the correct size for your chuck.
Some cordless impact drivers have an LED light for working in poorly-lit spaces. Some models have several LED lights positioned in a circle around the chuck.
Usually, the LED light will automatically turn on when the speed control trigger is pulled, and turn off when it is released. For more information, see our section: What is the LED light on a cordless impact driver?
Motor
All cordless impact drivers have a motor inside the tool’s casing.
The motor converts the battery’s electrical energy into mechanical energy giving the rotation required to turn the chuck. The motor’s power is a combination of speed and torque.
The forward/reverse switch allows you to alternate the direction in which the chuck turns. Forward (clockwise) is used to insert screws and drill holes, reverse (anti-clockwise) is used to remove screws and back out drill bits.
On some models, pushing the forward/reverse switch into the central position locks the impact driver in the ‘off’ setting, allowing you to change between bits without worrying about the chuck turning and causing injury.
The cordless impact driver is operated using the speed control trigger; pulling the trigger starts the chuck turning. The further you pull the trigger in, the faster the chuck turns and the more you release the trigger, the slower the chuck will turn. Releasing the trigger completely stops the impact driver.
Grip
This is where the cordless impact driver is held. Some models have a rubber grip and some just have contours in the plastic casing.
Rechargeable battery
Every cordless impact driver has a rechargeable battery that can be removed from the tool when it comes time to charge it.
The three most common types of battery used in cordless impact drivers are: nickel-cadmium, nickel-metal hydride, and lithium-ion. Each have their own particular set of characteristics.