What are you guys using for a source of grinding wheels for an 8" bench grinder? I bought a new Kobalt medium grit 8" wheel (MADE IN CHINA IT SAYS!) and if you grind on anything very hard it just turns the wheel to a pile of powder on the shop floor while polishing the part you want to grind!

I need an abrasive wheel that will grind something as hard as a grade 8 bolt without making grinding powder...... Any ideas?