I traveled to a manufacturing expo last year. I had so much stuff to bring back that I needed extra room in my carry-on. So I loaded it up with these: box of drill bits and some endmills (very sharp), set of dial calipers, set of metal files, small containers of superglue, a couple books of sandpaper, set of precision pins for measuring holes (basically looks like a bed of nails in a box). Also I had a bottle of water. Yep the bottle was confiscated but they didn’t care about all the other crap even if it looked like MacGuiver was planning to hijack a plane.