Skippy,
I suppose I ought to have mentioned the span-that was my concern. I agree totally with your idea for the triangulation-a much better approach! I got my idea for this from some Discovery channel show on the history of the arch-and you again are right-they only work in compression. I said tension due to the thought of bending the piece into its final position (I could try to save face and say that I meant the spokes would be in tension-but I won't-you got me).
Of course your original point concerning the upward reaction forces to the milling head still apply-and I'm wondering if Gerry's stressed skin beam isn't the best way to go-if the strength is there it'll handle loads in either direction.
Or maybe a combination. This is the problem with inexperience! Indecision.
Thanks again for the helpful input.
Lance |