Thanks to all for your replies. I suspected the same thing but unfortunately I cannot figure out how to get the tool apart further than disassembling the handle, which does not get me to the commutator. I can however see the brushes making contact with the commutator and the sparks flying while it turns. The copper on the commutator is all black but not pitted. Also, there was 2 small pieces of metal rattling around inside that I was able to pull out with needle nose pliers. I thought it had something to do with the sparking but it appears it did not.
As you can see in the photo, no screw heads exposed.