You should have made a treaded wooden dowel and glued that in. Then you thread the ferrule on. With the weight of the ferrule being heavier than the wood, you just created additional deflection.
Sorry but I own several custom cues. A couple by cuemakers that are in the international cuemakers hall of fame. None of the better cues have ferrets screwed in. Low end cheap cues ,yes
@muddymo7641 yes, that was the OLD way of doing things, when technology was not as far along. I'm not saying the way it was done is bad or wrong, but there are certainly better ways of doing it today. The old pressed on fiber ferrules worked well way back then, until they shrank and created a gap between the ferrules bottom and tenon base. Today we have thermoplastics and phenolic that does not shrink nor crack under normal conditions. Technology and methodology improves over time. Most also was reduced deflection, not more.