What does prior art mean?
Prior art also known as state of the art means something is not protected by any property right (anymore). It is free to be used by anyone for every purpose without any restrictions or conditions.
A good example is a string used to tie a regular knot. However. It might for example happen that you have a string from a new material. This material might be protected and not prior art. Therefor your string is probably protected. You have to check it case by case. Rule of thumb: go for the “boring”, regular solution that is around for decades and you should be on the safe side.
from sheep wool: prior art.
from wool but also with a wire inside to conduct electrical signals in wearables: might be protected.
a regular M4 bolt is prior art.
A M4 bolt though from a material that explodes for example or has an RFID chip build in might be protected.
So also with prior art. Look twice. Who made this part. And is something added that might be protectable and be protected. Go for the simplest, easiest oldest solution. And you’ll be sure.