My question is this--are there any approved connectors for rigid pipe, such as compression fittings, that I could use to make a solid connection (rigid to a junction box, or rigid to flexible conduit)?
I've rewired up to the box that feeds the fan/light, and I don't think there is any way to budge the old rigid to get new EMT or flexible conduit in (it is flush to the joists above). To make matters more complex, all four knockouts in the feeding octagon box are being used. I don't think I could get a threading tool onto the cut end of the pipe to cut new threads and add a junction box.
Any ideas would be greatly appreciated. I am not against breaking into the walls if this is the only way to solve the problem properly.