I had to replace the radiator hose on my wife's car a couple years ago and I noticed it was about the same diameter as the radius of a hollow razor. I shaped a broom handle to fit inside (shaped it a bit oval for different shapes) tightly and it works like a champ. About to use it with some knives that I roughed out the other day, handy booger.
I like the cork idea for two reasons: cork is a perfect backer & it gives me a good reason to obtain another cork! Kinda feeling like a Reisling right now...