This container was an experiment to see how difficult it was to create threaded parts that fit together. The critical issue is the amount of clearance between the male and female threads. Fortunately it only took me 2 tries to get this right.
Note that these 2 parts have Left-Handed threads, which is the opposite of normal.This means that to attach the top you turn it to the left, and to remove it you turn it to the right. I found it helpful to start by doing several partial on/off moves to wear off any slight bumps resulting from the printing process. The threads do fit fairly closely, so I imagine that if you tighten the top too much you might not be able to get it off.