2. As you can see, you can't see through the disc. It's like trying to drive in thick fog.
3. I use my pliers to make a notch on the disc. How much to break off? If the notch goes all the way to the screw edge of the mandrel, then it's too deep. Even with the notch, it will still cut like a new round one.
4. Now I mount the disc back on the flex shaft after the "enhancement."
6. Another look at the modified disc at high speed.
And of course, ALWAYS wear eye protection when using separating discs. A dust mask is highly recommended as that disc can kick up a lot of dust.
(This post also appears on the EtsyMetal Blog.)