I made a lamp.
Other parts:
Remix on https://www.thingiverse.com/thing:891147
Print lamp in vase mode. With concentric bottom to find the center later.
Print bottom upside down.
Update 2023: PrusaSlicer supports bottom layer openings in vase mode with modifiers!
I've now included a .3mf with a negative modifier for the bottom layer.
Not using prusaslicer? Then use the old instructions for the 41mm hole below.
Afterwards:
Slic3r doesn't support holes in the bottom for vase mode yet.
So you have to make a hole in the bottom. I put it on a kitchen paper roll and drilled many holes around the hole perimeter. Then with a sharp precision knife cut it out.
You can't see it when assembled, so not that important. Only to hold the top to the bottom with the fixture screw.
The author remixed this model.