I found this small aluminum item in a tool box. It’s 1.5" diameter. The two pieces screw together. I thought it was a little stash container, but the larger piece has a nub inside which would fill the void on the smaller piece when screwed together. Is this some tool? Or maybe a little machinist project.
If there’s any small gap left when it’s screwed together it could be a nitroglycerin tablet holder
That’s the first thing I thought of when I saw this.