Angle grinder trouble

[100%Chevy]

Dewalt,Black and Decker and Craftsman are pretty much the same grinder.
Sounds like you need new brushes.
Take the grinder with it's part/serial number to the nearest dealer or wholesale house and ask for the brushes.
They're easy to change out.
Also,take a piece of fine emery cloth(180 grit)and clean the black carbon off the commutator.It's the part of the motor that the brushes ride on.
The black carbon and worn brushes cause a bad connection and will make it throw sparks.
Less than a $10.00 repair.
Mike.