I shamelessly really don't want to report this one because I've frankly been using it to my benefit...however, my guilty conscious finally got the best of me...
If you drag a tinkering tool over to another tinkering tool, it lets you repair the broken TT without having the proper skill level (Tinkering III). Which essentially gives you unlimited TT repair ability with only purchasing two TT even if you don't have Tinkering III yet.
Okay, everyone can throw tomatoes at me now...and, yes, it's so going to stink when you guys repair this one...(please say it's an intentional hidden benefit in the game and not a bug)