I did something slightly stupid when preparing to mount a new fixture to a very old unused ceiling pancake box in a 96-year old home: I unscrewed the bracket that attached the mounting nipple to the box, under the assumption that I would be able to either re-screw it back in, or attach alternate mounting hardware. Instead, it seems that there were nuts holding in those screws, which are no longer aligned with the screw holes, rendering them useless as attachment points. I see no other obvious way to attach any kind of hardware to the box.
Ripping out the box will mean doing some violence to an old plaster ceiling that I'm probably not up for in the near term. Wondering if I'm missing some other option?
(ps, I know it's controversial to attach fixtures to old two-wire circuits. If it helps, I plan on updating the circuit breakers to Arc Fault Interruptors, and only use LED lamps in this fixture.)
Best Answer
How annoying! OK get a set of drills and start sticking drill bits up through those holes -- butt end first. We just need to know the hole size.
Now hit a "Drill and tap" table. Anytime you tap a thread into a hole, you drill the hole to the smaller size (tips of the threads). Go to the table under "Fine thread bolts" and find the fine-thread size whose drill size is slightly bigger than the holes you have. Buy the correct drill and tap, drill, and tap.
Now you have what you thought you had in the first place.
You need to use fine-thread because coarse-thread won't have enough purchase.