Before mounting the ferrules to the rodshaft the serrations that will slide onto the rod shaft has to be tapered. There are two reasons for this. First when the ferrule is wrapped, the thread will make a smooth transition from metal to the cane. Second, the thinner ferrule walls at the serration allow for a smoother transition of energy from the butt to tip when you are casting your bamboo flyrod
Ferrules ready to be glued to the rodshaft.
Since the male ferrule is slightly oversized, you want to uniformly remove just enough metal from the male ferrule slide so that it fits firmly into the female ferrule. ..... a cup of coffee and out into the sunshine, do not need to be working in the basement for this job