I'm still waiting for delivery of my first printer, so I thought I'd pass the time by trying to figuring out the process. I modeled this off of one of the lamps in my living room to see if I could get something from Rhino, to an stl, then sliced into some gcode.
There is a 5.7mm hole that goes about half way through. That was the inner thread diameter I measured. It might need to be a little larger to screw on nicely. I'm curious to see how the printed hole diameter compares to the one I measured.
Edit: Well I finally got the printer. I attached a photo of the printed version and the original. I think it turned out excellent. the hole ended up about 5.6 mm, so not too bad on the perimeter width.