Review on Finest Ingersoll Rand 9800 Die Grinder Stones for Professional Precision Grinding by Ben Diesel

Great price but so-so packaging. The back of the card should have a list of the materials each stone works best with: aluminum, steel, cast iron, etc. As a hint, you can dip the stone you're working with in gear oil (any kind will do). ) every 20-30 seconds to keep the material from accumulating on the surface of the stone and rendering the stone ineffective.