I have a Dremel Moto-Tool that I use occasionally for small cutting or grinding jobs.
When buying a Dremel tool it usually comes with a few miscellaneous bits and wheels. The cutoff wheels that are supplied are normally the stone type. (above left) These are very inexpensive, but are so fragile that they are almost useless. The fiberglass reinforced type that is shown on the right is more expensive, but works much better. They cut almost anything and last a long time.
If you stack three or four of them on a mandrel the wider surface works great for grinding. I use this trick occasionally to grind a welding job that needs great precision or is in an awkward location.