Hi, if you ever want to throw an angle grinder, you better not!
Inside this grinder you will find a 90 degree gear that can be used both for the reducer and to change the direction of an axle.
You can also take the bearings from the angle grinder, part of the rotor shaft, the brushes can be used at another angle grinder, you can also find some plugs and contacts.
I use them and give good performance to 18-24 volt motors to change the direction of the shaft and to reduce the motor speed to smaller projects.
For example, using two identical sprockets can create a differential, only a housing must be built.