Tell us about yourself!
Sure you can buy a rotary tool for cheap, but the pleasure taken in creating your own tool is priceless! I also tried to make a similar rotary tool and used the same disk attachement salvaged from a wire conector that you used. I quickly found that it wiggles a lot, and in little time the disk described an eccentric rotation. To solve that problem, I bought a mini drill bit on e-bay for a couple of euros. Wasn't too expensive and works just fine.