This is pretty cool!

I noticed the author decided to use metric thread machine hardware. He's probably an American because he specified McMaster-Carr as a source.

#4 and #6 machine screws are a lot less costly here and available everywhere. (Your hard drive screws are 6-32, same as the electrical wall boxes; floppy 4-40)

I personally hate unified threads, on the basis that the rest of the world uses iso threads. But this is one of those times that being a pedant about it would increase the cost.