All of these tools are based on things that were one-offs of earlier efforts, and turned into practical machine tools by someone that history chose to remember. We're now at the point where making things by manipulating individual atoms is something a determined amateur can do, it's amazing!
I find myself fascinated by the Wyler Inclinometer, which uses a thin copper disk with spiral arms as the basis of a differential capacitor, and when complete, resulting in a device that can used to calibrate a granite surface plate. It can typically measure 1 micron/meter of deviation.
We now have 3d printers that can reliably make almost anything you want by fusing filament, or stereolithography, or fusion of metal powders. You can buy desktop 5 axis CNC machines. There are control systems available to let you build almost any type of machine tool you can imagine, in as many axis as you want.
We've got software defined radio, cheap atomic clocks, transistors that can switch megawatts, all within reach of a hobbyist.
What an amazing time to be alive.
And the channel's preceding few videos covering the development of the prerequisite technologies.
inspired by Jeri Ellsworth, who also documented hers on Youtube: https://youtube.com/playlist?list=PL5DCEA197C1C07A2D
It is actually a great example which shows the difference between cobbling something together in a garage, to produce a one-off demonstration, and having a mini-fab which is capable of delivering the results reliably. The difference in the required effort is many orders of magnitude.
The "RAM in a shed" guy started with a Ph.D. in semiconductor technology, and was running a company before he made the improvised lab at home and started to make videos about it. He uses the lab to test some of the steps for the specialty devices which he invents.
Different forces and material properties are all at relatively different levels.
The one I know offhand that will mess with stuff is the square-cube law. If you double the linear dimensions of something, it's twice as big, linearly, but 4 times the surface area and 8 times as heavy. The strength of anything that depends on area (like friction) won't scale at the same rate as anything that depends on mass or volume or anything.
Not to mention I'm sure this thing can only print a few different materials. Unless those are also _all_ of the materials it's made out of, it couldn't even make itself.
But even if you could get a positioning system that small, I'm pretty sure you can't scale resin printing down three orders of magnitude smaller than this printer. Maybe a tiny CNC?
Or more likely they refer to eventually printing the mems devices used in the printer
But simply making something smaller is not synonymous with it automatically becoming more accurate or capable of achieving higher resolution. If anything, very high precision machines are typically larger in size than the less accurate ones.
While a large piece of sheet metal might slide down a given ramp, a 1/1000 scale bit of foil of that same metal would probably just sit on that same ramp and not move.
There are lots of constants that, by definition, don't scale.
But you can get etched glass scale encoders that will give you 1um accuracy for basically nothing these days (IE <50 bucks).
You'd still be better off just using cheap linear motors with encoders built into the rail though.
Being able to make structures this small could maybe make DIY inkjet printers viable, if you can simplify them enough?
The most exciting are the applications nobody has thought of yet
Piezos are sure the way to go for a fab-in-a-shed youtuber, but not yet for those who want to make it reproducible by others.
After playing around with several options, piezoelectric was the path I chose for a sub-micron stage. It took a bit of research, but it does make things much easier when done right.
Most hobby work is kept private now... due to safety issues with people without lab-training attempting complex builds. Indeed, a few fools still die every year attempting things they saw on you-tube ("Lichtenstein burning" etc.) =3
To look at the output they recommend a separate regular microscope