I have looked over multiple wikias all of which mention need to have "knee joints" (as well as in-game page). Questwalker's interactive map shows that all of these joints are inside TRs, but the screenshots provided are very different from 0.82 I'm playing. I have even started a new save file to check that my actions might've resulted in TRs looking different (breaking shelves, workbenches, stuff like that?) but no, there are no buckets with joints, no shelves with joints, no joints under workbenches. In fact, there are no buckets, shelves, or workbenches in the first place! So, I now have no idea where to get these joints, except editing a save file or doing with the sandbox mode.