Impressive!

Suggestion: It would be nice to include a price list on the article.

This project is impressive as heck, but aside from being intellectually out-of-reach for most kids, it would be financially challenging as well. Last I looked, CNC aluminum blocks were well out of the reach of 99.9% of kids (but that was decades ago; perhaps prices went down).

For people wanting to follow in those footsteps, it'd be nice to know which things cost $5, which $50, $500, or $5000. Just that kind of intuition is helpful.