Two-part epoxy was also tried, which matched the un-threaded holes in strength. So for resin parts you’ll probably be best served by just modeling the threads in CAD and printing them directly.
They build bells out of metal, so that might not be the best if you want something that doesn’t shake. Epoxy granite is your best bet, but what epoxy granite is the best? That’s the question ...
EP30-2 cures at room temperature or more rapidly at elevated temperatures. This epoxy flows smoothly and evenly after mixing, and is easily applied as an adhesive, coating or potting material.