currently only things you could theorhetically DIY with enough knowledge, skill, and readily available equipment are considered for adding as craftable.
what if you found a rivtech factory though? or a semiconductor facility? these things could be really hard to get into, lab fanale rare, (gun/hightech factory would be locked down hard), require lots of skill, and some manuals to operate the equipment, but you should be able to run it in some cases to produce a factory made item.
I don’t think it would be a standard crafting recepie though: You are more running equipment than crafting an item.
of course, it wouldn’t make much sense to implement before the locations that support it, but labs could have some of the machinery to make certain items (CVD machines fit this model really).

Somewhat planned out here:

Development stalled due to IRL distractions and lack of machine shop knowledge. If someone were to json out a good 2x2 machine shop and the terrain for it, I’d happy do the rest of the coding.

read the thread there, and there were some interesting points, I was thinking however more of complete purpose made factories, which avoid some of the contentions over there. specifically: due to increasing use of robotics, the production of assembly-ready parts in a factory would only require a design, and a little computer / fabrication / mechanics skill, some high-yeild processes might even go from high-quality input materials to finished product with no human interaction (after the process is initiated).
Difficulties would include:
purpose made equipment may only be good for 1 thing. (the less you have control over the process the less options and difficulty you have.)
manufacture of the high-quality input materials.
power generation.
in some circumstances, synchronization of a process may be very difficult or impossible on your own

an additional point from over there that was shot down quickly for seemingly little reason was increasing prevalence of 3D printers.
one of the negatives for a prototyping machine that was given was wasted materials, but current 3d printing wastes relatively little.
the most prevalent material for 3d printing is plastic, but metals, foods, and even organic material are starting to be used.
The most common method of printing is a melted plastic extrusion process, yet some use photosensitive materials and a projection system or lasers to harden it. metal printers can use a laser sintering process or electron beam sintering to make finished products (not just prototypes anymore) even titanium aircraft parts are being made this way.

the fanciest ones are of course very expensive, big, and rare. they only require relatively low ability compared to traditional manufacturing however, and are very versatile.

This of course raises the question of ‘What now?’

You find this factory. It’s big a glorious. You can melt down cars and televsions and create basically whatever you want. Raid labs, bunkers, whatever, you can build all that high-end crap with enough time and grinding.

And thus, “What now?” gets asked. You can kill everything. All devices are just becoming overkill for the kind of monsters you can expect to encounter, even the rare and lethal ones. That’s it: that’s the peak. You’ve reached the end of what the game has to offer. You “win” the game.

And then the player puts the game down and does something else. Future updates get ignored because they’re burnt out on it and maybe they’ll get around to looking at it, maybe they’ll just delete the files and forget it ever existed.

The game needs a lot more length before it gets more bling. Anything considered “end game” is just putting off the boredom that comes when you realize you don’t have anything else to do yet.

That’s a tricky thing to balance and consider, even as things stand there is always a point where you have nothing left to do. this could be helped in this instance by having plans scattered far and wide. with no internet, acquiring knowledge is a little trickier. Making high end devices gobble up power would help a little, and refining resources might take a goodly amount of work.
then there is the way that DF and MC get around it: opening up creative possibilities. the more designing of your character, the world, and items you can do, the less lack of content becomes a problem. more dynamic NPC interaction could also alleviate that I think.

How about a nanite forge? We have enough rather advanced technology to have something like it. (also referred to as a replicator at times) Like the guy said, high end lab item. I’d envision it as a heavy vehicle part. Using it would use up it’s nanites. Nanites would be found in the labs. Along with high end blueprints that could only be made with such a device. Also the rare materials that such recipes would require. (suggested different types of labs a while back, materials, energy, fabrication, etc…)