Review on SPTA Proxxon Aluminum Grinding and Polishing Tool by Andre Belitz

I bought these to use in my Dremel variable speed power tool. They fit perfectly in the tool holder. I bought them to specifically remove rust from a steel planter. Lots of curved swirls, flat metal and edges. They worked very well as long as the bit stayed securely on its post. Where they tend to fail, the sanding head detaches from its metal post/pin. Whatever method they use to attach the whetstone to this stand fails. I'm guessing it's some kind of glue. If it fails, the whetstone simply stops spinning/grinding and the pin/pin spins within. I paid attention and can't exactly say that the collapse was due to the whetstone sticking to the metal. It's possible, but then it doesn't have to be a metal grinder. So I would say they have a bounce rate of around 35% and up. I haven't used all of them and am almost done with my project. I sanded off the rust and paint and went down to bare metal. I did most of the sanding with a resin sponge and a sander, then moved on to the Dremel tool for scrolling, edging and flat metal in tighter spots. The pieces going further were fine, they got narrower which allowed me to get even closer to some of the scrolling and edging work. Definitely worth it for the price.