Ferrule
From The Angler's Dictionary — your encyclopedia of fishing rods, reels, and tackle
A ferrule is the joint where two sections of a multi-piece fishing rod connect. On modern graphite rods, the most common design is a spigot ferrule — the upper section has a slightly thinner, solid tip that slides into the hollow end of the lower section. Quality ferrules are engineered to transfer energy smoothly across the joint so the rod bends naturally, as if it were a single piece.
Older and some specialty rods use metal ferrules — male and female sleeves that friction-fit together. Metal ferrules are durable but heavier and create a stiff spot in the rod's flex pattern. Modern spigot ferrules, when well-engineered, produce a virtually seamless connection that is difficult to distinguish from a one-piece blank in terms of action and sensitivity.
When assembling a two-piece rod, push the sections together with a slight twisting motion and align the guides. Do not force the connection — the ferrule should fit snugly without extreme pressure. When disassembling, pull straight apart with a gentle twist. If a ferrule becomes stuck, grip each section with rubber pads for traction and pull evenly. Periodically clean the male end with rubbing alcohol to remove dirt and oils that can cause the ferrule to seize.