> An amateur can, with care, skill and some money, work to microns.

I love how you can start with really rough tools (like wood and stone tools), and iteratively create more and more accurate tools, to the point of rivaling commercial tools.

I mean, that's how we got here. In the grand scheme the time from using rocks to make fire (flint) to putting electricity into thinking rocks (silicon) to throwing refined carbon into space was very short. Amateurs stacked on amateurs from only 1600 mothers ago!

It's only been 340-ish years since we started on the electricity tech tree in any rigorous sense. That's 16 or 17 moms ago, at most. If you had a durable, stable culture 200,000 years ago and dropped a series of carefully selected experiments in their laps, they'd have been able to create with electricity with as much brain power as we have today.

Still, we had thousands of years of cultural experiments to survive to eventually arrive at a confluence of social structures that allowed for us to explore science and rational natural philosophies.

From the Greek mathematics and Sumerian city states to Roman empire building and onward, we carry pieces of those things that perform best at giving us life less full of struggle and suffering.

A smartphone, seen from Kurzweil's view of human progress as a function of structured information, you get a sense of being present for something vast and terrifying and beautiful. Stacked amateurs all the way back to the brave little rodents thriving after the dinosaurs died.

That reminded me of the poem The Calf-Path

https://poets.org/poem/calf-path

Thank you!

>>They follow in the beaten track, And out and in, and forth and back, And still their devious course pursue, To keep the path that others do.

Could you point me to some resource on how would such a process look like?

Start with researching the "three plate method" to generate a flat surface. A flat reference plane is the first thing you need to make precision machines. (The second is an accurate way to divide a circle.)

But the three plate method is one of those foundational, from-first-principles realizations that changes everything. It basically means you can start with three rocks and manufacture your own reference plates that are accurate in flatness to any arbitrary tolerance you have the patience to achieve.

With a truly flat plate in hand, you can generate a reference square - again, to any tolerance you like.

If reading about that stuff (it's everywhere on the web if you know the right codewords "three plate method"), your next step is to find a copy (electronic, probably, it's long out of print) of Moore's "Foundations of Mechanical Accuracy". I keep a copy beside my bed so on nights when I can't sleep, I can caress the covers and ease my soul.

Thank you very much!

Aye. I have a pretty cheapo mill, 2k for the mill and 6k all in (most expensive sector is metrology)*

Can easily work to under 0.01mm which is absurdly small when you're faced with it.

Then you see the guys working under 0.0002/1 and... it's just incredible.

> gets as close as any human endeavor to actual perfection

Truly. The only thing that matches it in terms of the physical is Xnm chip production and atomic level physics research. But those are far less hands on, and require tens of millions in equipment (plus the parts areade by machinists anyway).

* can provide running costs breakdown if interested

> (most expensive sector is metrology)

Absolutely. But ohhhh... those instruments. I saw a friend with an electronic gauge put it on one end of a 1' bar of steel. He put the gauge on one end and zeroed it. Then he breathed on the other end. We watched the needle cliiiiiiiimmmmbbb.... then fall back to zero over 3 minutes or so.

Holy crap. Is this because the steel expanded an infinitesimal but somehow still measurable amount?

Yes exactly. I was blown away (ahem) and instantly regretted my life choices, which until that point had not involved microns in any way shape or form.

The instrument readout looks like this: https://www.perfectionmachinery.com/assets/item/hires/40961_... except his had adjustable ranges. Every tick on that needle is one millionth of an inch - by comparison a red blood cell is about 40 millionths and the smallest bacteria is about 5 millionths long. This instrument has a read head connected with a cable, that has a finger on it that rests on the part under test. Under normal use you'd slide the part around under the finger to look for variations in thickness - obviously that requires and extremely flat surface to slide around on.

Yes. There's a joke in machine shops working to insane tolerances.

"just breathe on it till it measures in spec"

There's a great video by oxtoolco on youtube where he's seeing which is "thicker". A sharpie mark or some machinists blue. Measuring in the millionths of an inch.

Spoiler: a sharpie mark is about one ten-thousandth of an inch thick (depending on color, because size of the pigments!)

An interesting use of this bit of trivia: when machinists are trying to grind a block square, they may measure a slight deviation from 90 degrees - i.e. they see that each of the two opposite faces are parallel, but the angle they make is out of square. They have a parallelogram.

If you draw it, you can see that if they put it back on the grinder, and shim one edge of the face contacting the table, when they grind the opposite-to-the-table face they can bring it closer to square because they'll be grinding a wedge off the top face.

They use a quick swipe of a sharpie marker as a shim.