Review on 💎 Dremel Craftsman MTP Diamond Gemstone by Bud Crabtree

They hold up surprisingly well. I've used them on normalized, annealed, and hardened steel and as long as you're patient enough not to force them to do the job, they will. Let the ridges do their job at their own pace. You get 3 identical sets with 20 different burrs, which is what I wanted and in the few weeks I've had them I haven't switched to my "backup" or "backup" cutters. I find that they work best on my rotary tools at medium to medium RPM, anything in the high RPM range will cause them to wobble or speed out of their advertised operating range. Cooling down with a water spray bottle also improves performance.