Lathes can certainly make cylinders, and a tube-based lathe bed is not a stretch.

A lathe can't replicate its own assembly, of course. It can't seat the spindle in the constraint bearings, for instance.

A CNC (without the word lathe) can make most of itself, and possible all. Nope: certainly all, if two of its dimensions fit within its work volume.

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SAI_Peregrinus 6 days ago | parent | next [-]

Lathes can make cylinders, but not of unlimited length in one setup so they lose some accuracy making cylinders longer than their carriage travel. And their beds are by necessity longer than their carriage travel, since the carriage rides along the bed and isn't infinitely thin. They also can't make things like motor stator laminations, and you definitely need a motor for a replica of a motorized lathe. So lathes can't replicate themselves exactly.

Milling machines are also just lathes with a different orientation, an extra travel axis, and a motor optimized for higher speeds & lower torques, it's possible (and reasonably common) to use a mill like a lathe or a lathe like a mill in many cases. So "only machine" part is also a stretch.

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HeWhoLurksLate 6 days ago | parent | next [-]

if the purpose is to bootstrap, you could also use something like a leather belt drive off a central shaft, which would require different power sources but ones that a higher percentage of could be made with a lathe

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vdqtp3 5 days ago | parent | prev [-]

> Milling machines are also just lathes

Mills are more limited than lathe - they don't have leadscrews, which are a necessity in the "build yourself" phase. You cannot make arbitrary threads with a milling machine. Thread milling gives some capability in this arena, but that's a CNC process.

	▲	WillAdams 5 days ago \| parent [-]
		One can make arbitrary threads (vertically) on a CNC using a single point cutter (limited by the height of the Z-axis/thickness of the stock which one can fit a tool over/into): https://community.carbide3d.com/t/thread-milling-in-metal-on... A manual lathe will often have a gearbox which allows cutting threads on it: https://www.youtube.com/watch?v=E_KF3n3oo08

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jjk166 6 days ago | parent | prev | next [-]

But it can't make cylinders as long as its own guide ways.

	▲	ekaryotic 6 days ago \| parent [-]
		most lathes have a hole in the chuck to feed the work through. so if the material is ground down by hand to a diameter small enough to fit in the hole then to be turned and then removed and flipped over it's possible.

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fapjacks 6 days ago | parent | prev [-]

make me a truly flat surface

	▲	saintfire 6 days ago \| parent [-]
		It would be hard to make a human into a truly flat surface. I suppose if you have big enough granite blocks...