I made up my aileron interconnects today using the same size CF tube that Andrew used. Since these are less than 9" long, and for the sake of simplicity, I ran a piece of stainless 2-56 threaded rod all the way through. I figured that a couple of extra grams wouldn't hurt on a .40 sized model and I wouldn't have to worry about it being able to pull out. I didn't have any aluminum or brass tubing in the right size so I made aluminum ferrules and glued everything together with CA.