I wish I googled light microscopy first. I would make some Abbe condensed based. Well, maybe it will be my next project. But it works.
I used scaled down equivalent of 2020 extrusion. It is 10x10mm. It is severely overpriced on Amazon, and parts are way too small, but the whole thing is pretty usable.
The most challenging part was to connect to electric pads on the light panel.
I needed some holder for the frosted glass, and I decided to cut it out from a 5mm board and glue together. (No, 3D printing was not a good option since the LED panel heats up quite a bit)
Here is my design:
Lesson learned: There is no way in FreeCad Path to mill out a staircase with stair width larger-or-equal to bit diameter. It is somewhat possible to mill the first step from the top by milling-around the top surface and manually moving the path down. For the other steps you are out of luck. Get a thinner end mill. Ok, fine, my bit is wider than the stair surface. But there is an edge I could of mill along – may I? Sadly that kind of micro-management in not available in FreeMill Path.