I have an old Dremel Moto Tool Model 396. It has 5 speed settings ranging from 5000 to 30000 rpm. I have set up a jig to allow me to use it as a fixed small disc sander. Even the lowest speed setting is (to me) too fast. Is there something that can be used to further control the speed?
It is a 240 volt model with brushes and rated at 0.9 amps

It is a 240 volt model with brushes and rated at 0.9 amps
