Our home is approx. 120 years old and has nine doors using the glass doorknobs with threaded spindles. The problem is that with time, the knobs pull off the spindle and no amount of resetting and tightening the set screw on the knob will keep them in place for longer than a week or so.
At one point I wrapped a few rounds of teflon plumbers' tape around the spindle thinking that it might increase the diameter enough to create a better hold. This lasted a few weeks longer than usual but eventually the knob pulled off the spindle.
I'm tempted to wrap some epoxy resin putty around the spindles for a permanent solution but shudder at the thought of ever having to replace them. Does anyone have a better solution?