Why the grinder of the sink do not work?

The grinder, or garbage disposal, may be broken for a number of reasons. If you are using it correctly and cutting items small enough for the grinder to handle before placing placing them down the drain, and using water while you run the disposal, there shouldn't be a problem. If you are using it correctly and the grinder still isn't working properly, the problem may be a broken belt or a worn out motor.