Update to Experiment 1: Hard Drive Sander

As I said in a previous post, I ripped apart an old hard drive and made it into a disk sander.  My power supply for that sander finally arrived!  I tried plugging the sander in and then plugging the PSU into the wall while its switch was on, but nothing happened.  After some frantic hair-pulling trying to figure out if the supply was dead, I found a solution on the Internet.  PSUs need a signal from the motherboard to actually turn on, even if they are plugged in, so jumping the green wire to a black wire on the motherboard connector fakes that signal.  I tried this, and amazingly, the HDD spun up and became a high-speed sander!   I was able to nicely sharpen a railroad spike into a chisel for chopping stuff.  I also sharpened a wooden dowel into a conical point and gave a regular pencil an unnaturally sharp point.  I noticed that after 2 minutes, the HDD spontaneously shut down.  The PSU's fan still was spinning, but the HDD consistently shut down.  However, I can cycle the supply by flipping the switch on and then off to fix the problem.  I believe that the HDD figures out that there are no signals from the motherboard and then decides to shut off.