Wow, what an interesting thread. So many opinions. I would like to input a few. A tool post grinder is just that, it grinds. A big difference when comparing it to the cutting action of a tool bit. Hard materials, interrupted cuts, surface finish, tolerance control to name a few are jobs for a grinder. A 1/8hp motor should be able to handle 2” diameter stones. Aluminum can be ground, but I would not do it all day, the stone will eventually load up. Frequent stone dressings (coarse) would be a top priority. IMHO a Dremel is not in the caliber of any tool post grinder, and one that is properly homemade. AND the most important of all, protect your lathe from the grinding grit/swarf. I would wrap the lathe with an easily tearable material, like newspaper. And when you are done, just to make sure, give your lathe a good cleaning. If you have or can find a tool post grinder for your shop, I would say definitely get it. When you need it, there is no substituting…Good Luck, Dave.