What is spindle lock?
Most cordless screwdrivers have a feature called spindle lock. When spindle lock is selected, the chuck is locked and cannot rotate.
Automatic spindle lock
Some cordless screwdrivers have automatic spindle lock, which means that the chuck is automatically locked as soon as the speed control trigger is released.
If the spindle lock on your cordless screwdriver isn't automatic, then it will need to be selected by hand.
When to use spindle lock
Loosening or tightening screws
Sometimes, it can be hard to start removing a screw using a cordless screwdriver if its very tight. The cordless screwdriver can slip out of the screw head or may not have enough power to start removing it.
When spindle lock is activated, you can use the cordless screwdriver like a manual one, controlling the pressure on the screw and the speed at which you loosen it.
Spindle lock can also be used to finish off the tightening of a screw, so that you don’t drive it too far into the surface of the material.
Inserting or removing bits
Spindle lock locks the chuck so you can insert and remove metal bits without it rotating and causing injury.