Demo case with tapered holding mechanism

I developed some microwells for use in my day job ( http://tinyurl.com/6bm6bth if anyone's interested), and when I am e.g. presenting a poster it's useful to have some examples to show people what I am working on. I made this demo case a couple of years back to hold them and keep dust out etc. I am posting it here as someone asked about strategies for fitting parts together - in this case I have tapered the interface between the two parts (look closely at the join between the wide and narrow sec