On the source-available piece:

I'm not saying I'm for those over open source licenses in general, but Prusa brought up some fair questions when discussing the OCL. Essentially: define "personal use." Have I violated a non-commercial license if I print this keyboard and then use it to build someone a website? Does CC-NC mean a Prusacaster -- or any guitar knob with such a license for that matter -- is strictly barred from being taken on tour? Or used to record albums that are then sold? (And I say "guitar" knob, but I'm choosing an example a little consciously that could exist in any variety of controls, instrument and otherwise.)

Where are the lines of that when it's physical things? How far downstream does that go if it isn't CC-NC-SA in particular?

I'm not really sure that Creative Commons had the idea of physical production in mind, given that it dates back to a time when we were more broadly talking about digital piracy, and I honestly haven't kept up with its evolution much in more recent years. But maybe it just doesn't make the same sense for designs of physical things, for comparable reasons to why it wouldn't make sense for code -- and, conversely, open source projects that opt to use CC licenses for assets.

(None of this would stop me from attempting to build/mod one for fun, mind you. It just raises what a more averse person might call risks, and what I will at least call curiosities.)

Yeesh. People. C'mon. It's okay to use some common sense here.

Keychron is a keyboard/mouse company. It is VERY reasonable to interpret "non-commercial use" as meaning "don't sell mice/keyboards built or derived from these designs."

NOT "we are going to sue you if a 3D-printed copy of our mouse ends up in the background shot of your movie," or similar contrived madness.

Not a lawyer, but as I understand it the license is a matter of copyright, and the copyright only applies to the design files. So as long as you're making that keyboard for yourself then you should be good to do anything you want with the keyboard, because it is no longer using the license at that point.

Now, what is interesting is if someone were to blatantly violate the license and start manufacturing commercial keyboards. I believe their only recourse would be to revoke their license of the design files, and then it would be copyright infringement. The thing is, I don't know how copyright law would handle any damages.

I don't know if making a physical product could be a violation of copyright, regardless of if you had a license to use the design in the first place. I could definitely imagine a company trying to enforce this, and a judge throwing it out because it should have been handled with patents.

Again, not a lawyer, just speculating on a forum.

Hasn’t Creative Commons disavowed or at least really downplayed the NC license for exactly these reasons? There are so many ambiguities and headaches involved that the only advice I’ve ever seen is not to use it.