This threaded ring holds the large diameter (~127mm/5in.) magnifying lens in those old 22W circline fluorescent lamps. My ballast died and I bought a new led based lamp of the same style, but I wasn't about to toss the lens, the springs or the hardware. I built this to hold the lens, to give you something to hold on to and to keep both faces off the work surface safe from scratches.
Geeetech i3 Pro B w/ mods
Print time around 3-4 hours for each piece with a relatively slow machine like mine.
I used black Hatchbox ABS@240C and hairspray to keep it stuck to my 90c bed.
Scale it up accordingly if you plan to anneal your print.
Be sure to scale up your print or annealing will shrink it just enough to no longer accept the lens, I'd recommend 2% but it really depends on the filament. Remember a little bit oversized still works, undersized doesn't work at all.
I annealed in a toaster oven @105C for about 30 min. Not necessary, but I like doing it.