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Comment by phkahler | Hacker News Reader

If Elon is serious about building a self sustaining colony on Mars, this stuff will be critical. Mining, refining, and manufacturing will all be critical, as will growing food and producing air and water. Finding a minimal technology tree for that is IMHO an extremely interesting problem.

Quick, what is the only machine tool that can copy itself?

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That would a lathe. The queen of machines. More specifically a screw-cutting lathe .

Could add a link but you will have more fun digging your own rabbit hole.

An as a rule of thumb, if you fall into this hobby, you are allowed one per decade old you are before it it has a hording disorder smell.

the lathe is basically the one machine required to kickstart the industrial revolution. (and a way to drive it ofcourse).

Also, three surfaces that can be ground truely flat is also vital.

i can highly recommend the youtube series "machine thinking" if you have interest in this[0], aswell as the book "the perfectionist"

[0] https://www.youtube.com/watch?v=gNRnrn5DE58 [1] https://www.amazon.com/dp/0062652559

Although truly flat surfaces can be easily generated (relative to building a screw cutting lathe from scratch). It just takes a lot of time and labor, but lapping two granite plates together would produce a good-enough surface plate; considering the accuracy likely to be achieved with a one-off homemade lathe.

Realistically, the absolute hardest part would be the castings. Cast iron is no simple feat, as I'm sure the future posts in this series will show.

Lapping three surfaces together is the path to flats.

Lapping just two together is how we make concave/convex hemispherical pairs for telescope mirrors.

https://en.wikipedia.org/wiki/Flatness_(manufacturing)

The Gingery books' path is via cast aluminium.

Here is a video series of someone building the Gingery Lathe: https://www.youtube.com/watch?v=zPGZg45dGXA

Aluminum is going to be much harder to manufacture on Mars than iron, at least initially, because it requires so much more energy to process.

Cast iron is much easier than steel. You won't get to the lathe without cast iron (and what will you lathe anyway?)

You can make a lathe from other materials. Most people building one in their garage these days use aluminum. Cast iron is better in a lot of ways, but the temperatures of aluminum are much easier to deal with, and today we can get good aluminum alloys to work with. You can also use bronze if you wanted. Granite is probably better than cast iron if you design for it. Concrete has been used commercially.

Many people don't realize it but you can put a cutting tool into the chuck and use the lathe a (limited) horizontal mill.

Shown here https://www.youtube.com/watch?v=i2cgoPpCmPc, note that on this video he's making yet another jig for the lathe.

This is an interesting little website showcasing this kind of "tech tree" idea :) - https://simplifier.neocities.org/

For metal specifically this technology will be vital:

https://www.bostonmetal.com/

They figured out how to refine iron out of iron ore without all the usual steps.

We don't have coal on Mars. Everything need to be driven by electrochemistry.

Check out:

- https://www.youtube.com/watch?v=-pYNzxorJs0

- https://www.youtube.com/watch?v=pg5M5WjGx5M

I'll bite at bending the meaning of 'machine'.

The Human / Operator; an advanced product of millions, or was it billions, of years of evolution which is self replicating (in the right pairs at least).

I give up, what is it?

Technically, a lathe. However, it very much depends on how you define "can replicate itself". You probably need at least a foundry to melt metal as well to do it truly "from scratch" and I'm not sure you can make one completely with a lathe.

The Gingery machine bootstrap is one of the coolest things which has ever been written.

It's relaxing, to know that there's a technological floor below which humanity can't fall, given literacy and a collection of seven books. And it's a pretty high level of technology.

I kinda love that while you can't make books with a lathe, you can make the tools (to make the tools) for a printing press with a lathe so it still mostly works.

Required song after saying 'from scratch': https://www.youtube.com/watch?v=zSgiXGELjbc

I think the answer is often "the lathe", but I also think it depends on what you call a machine tool and how persistent you're willing to be.

a CNC machine.

Also a blacksmith hammer.

a CNC machine can't copy itself, unless you have a CNC machine which can make a computer powerful enough to run G code.

Which would be very cool, don't get me wrong...

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