First some background.
I have this 3D printer that sucks, is pretty expensive, and unreliable. Whenever you need a spare part, the manufacturer sells you the entire kit! I needed a thermistor and they wanted to sell me the entire kit for $250, not only that, some pieces came 3D printed with pretty lousy quality and broke over the last 8 years, and not only that I've had to send the printer back 3 times because of many issues.
That said, I reverse-engineered all the entire 3D-printed parts, and want to share the STL files to whoever needs them. Also, I'm working on a mod to get rid of their crappy hotend and once I'm done I want to share it for free with whoever needs it. It's hard to spend a lot of money on a piece of useless crap, and if the manufacturer is not going to do anything to help or fix the issue then it is up to us the users to do it.
Knowing that the manufacturer won't provide these parts even if you ask them, they will sell you the 3D-printed parts with the lousy quality they initially came.
So my question is, is it legal for me to share these STLs after I reverse-engineered them, as well as any mods I come up with for this printer? The last thing I would want is to get into trouble for trying to help someone.