When I have to make rudder linkages etc I use the soft iron wire that is used to fix re inforcing steel in concrete. It comes in two sizes, 1.6 and 1.8 mm.which fit the holes in servo arms. Is easily ciut with pliers and completely malleable (Bends easy, for those that don't know what Malleable is!) Find a building site where they are pouring concrete Foundations or floors, and ask one of the Gorillas there for some.It comes in rolls about as big as an egg, last for ever! Also useful for binding bits together while glue dries, fix by twisting ends together. Doubtful? Well I used it on Throttle linkages and steerable nosewheels on Planes for years, never let me down, or the plane! Can make adjustable linkages by useing a short Z end on each control and join with a double screw electrical connector. If that is confusing maybe I should post a photo!