I've been using Beman brand CF arrow shafts for pushrods for some time now on both small .40 size to gas powered aircraft. I turn a dowel down to a slip fit within the shaft, glueing about 3/4" of the dowel into the shaft. I use medium super glue or epoxy - doesn't seem to matter as long as the surface is clean/dust free (big hint). I suppose it wouldn't hurt to roughen the inside walls up a little with fine sandpaper to improve adhesion, but I haven't bothered and it's worked OK. I drill the dowels ends to accept a length of 4-40 or 2-56 fully threaded rod which I glue in using medium CA. I usually cut the threaded rod end to about 1 or 1 1/4" length. It's that simple, and works great.