> So much of the modern world depends on our mastery over materials (to make a precision screw, you need a precision-machined harder material—diamond / titanium—to work on a softer material—steel), and our ability to turn rotary motion to linear motion (it's stupidly difficult to reliably precision-machine a harder material without even more precise linear + rotary motion—lathe/CNC machine). Hence, a bootstrap problem.
Steel is hardenable (or rather, some steels are hardenable), you can change its hardness through the specific application of heating and cooling. So you can make a crude tool with relatively soft steel, harden it, and use it to make a more precise steel tool (again machine soft, then harden). This does make the bootstrapping problem a bit easier, I think. Although not easy in the absolute.
> So much of the modern world depends on our mastery over materials (to make a precision screw, you need a precision-machined harder material—diamond / titanium—to work on a softer material—steel), and our ability to turn rotary motion to linear motion (it's stupidly difficult to reliably precision-machine a harder material without even more precise linear + rotary motion—lathe/CNC machine). Hence, a bootstrap problem.
Steel is hardenable (or rather, some steels are hardenable), you can change its hardness through the specific application of heating and cooling. So you can make a crude tool with relatively soft steel, harden it, and use it to make a more precise steel tool (again machine soft, then harden). This does make the bootstrapping problem a bit easier, I think. Although not easy in the absolute.
See https://www.youtube.com/watch?v=V_Mp1fNzIT8 for a great dive into primitive steel hardening techniques.