Build a Tesla turbine from 2 old computer hard disk drives using basic hand tools and a pillar drill. No metal lathe or other expensive fabrication machinery is required and you only need some basic craft skills. It's crude, but this thing can scream!

I have published the design on one of my favourit websites, Instructables - the World's biggest Show&Tell, so go check it out:


Here is a longer video of it in operation, running at approximately 20,000 RPM and generating a clearly-visible gyroscopic and precession effect, which was a nice extra to the experiment: