Hi Ross,
Engraver? Yes, I guess it is, but I tend to think of it more as a thing with a spinning cutter shapes that stuff by moving it three ways against the cutter. I must admit that I rebel against the idea of having only a single rail, too much like a narrow guage railway. On the other hand, Zapp have got some interesting profiles in their used/surplus section which I am trying to work into my Turbocad model. The topology of the machine in the site you pointed me to is similar to mine, except for the single rail and that my construction for the non-moving parts will be of 15mm steel plate.

Mike