Disc Sander from Old HDD

For shortening a screw on my Hadley telescope project, I needed a sander. I checked belt sanders and disk sanders. Then of course I wanted to try building my own. I was thinking about convoluted designs with belts and bearing, but then I saw old HDD’s I have been hoarding and decided to try them. To my surprise, it simply powered up and kept spinning when I applied 12 volts and 5 volts to the SATA pins. I added a buck converter inside so I can use it with just supplying 12 volts. Then I removed the spinny parts and made a 3d printed adapter. I covered that plate with velcro, and it was ready! In the hindsight, I could have kept the original disc and covered it with velcro, and cut out the middle part for the sanding discs.