As I've worked on my robot arm project over the last semester, I've spent a lot of time in the machine shop fabricating parts. I think it's incredibly fascinating that it is possible to create tools which have such high precision and rigidity that we can hold +/- .0005" tolerances! Even more incredible is that these tools, by necessity, were originally created from less accurate ones.
With that in mind, I've become very interested in how this is done. What processes are necessary to go from having no metal tools whatsoever to a full-fledged industrial machine shop? We have the technologies developed, and I feel it would be possible to use the knowledge that we've accumulated over centuries to quickly undergo that journey again. I think this would be an incredibly useful survival skill, and extremely practical to boot.
So what would the steps of this process be? You'll have to forgive me any omissions, I'm only just beginning to think about this. From my view, this would be the ordering:
Ceramics. These are necessary to create crucibles, and containers for the manufacture of many types of tools which can be used to fabricate other tools. Simple knives, chisels, files, and bricks are necessary for the next phases.
Charcoal manufacture. Using bricks from the development of ceramics, which could be cured in a dried-brick kiln, one would create charcoal for fueling the furnace needed to melt metals.
Smelting/Casting. Once sufficient stores of charcoal are made, and crucibles are available, the melting of metal (I'm not including mining ore here) begins. Some careful innovation with regards to which tools can be used to lift the crucible will be necessary, but the first tool made with this process can be a crucible tool, which will make things significantly safer!
Refinement of tools. Using abrasives such as fine grit sand and naturally occurring minerals, castings can be refined into more useful tools.
Metallurgy. Using the crucible, furnace, and charcoal, it would be possible to manufacture the necessary components for a blast furnace which could be used to make steels. These steels would be very useful for creating more robust tools.
- Machining. Now, with the blast furnace steel, better tools, and castings, basic machine tools can be made (David Gingery style). A lathe would be first; and used to manufacture the parts for a shaper, both of which can be used to make a mill.
Once the mill is done, you're all set! You have all of the components of a basic machine shop, and the capability to manufacture more as you see fit. This is what I estimate the progression would be, with each step building on the ones previous. If anyone has any experience doing this, I'd love to hear about it!