Michael Morgan had been supplying castings for same, and someone on the Practical Machinist site had been as well. It's a camelback with the bevel on one edge so would be a better head start than a straight bar which would not be nearly as rigid.
"I am often asked how radio works. Well, you see, wire telegraphy is like a very long cat. You yank his tail in New York and he meows in Los Angeles. Do you understand this? Now, radio is exactly the same, except that there is no cat." : Albert Einstein