> can someone tell me why we need cast iron back plates for our chucks. IIn addition to the stiffness issue mentioned earlier, keep in mind the
> never see anything mentioned about building back plates out of aluminum.
sonic energy issue, probably correctly called "phonon propagation".
Cast iron eats vibrational energy! The ultimate machine tool would not
only be infinitly rigid, would be vibrationally dead.
Cast iron comes much closer to the ideal of "dead" than anything else
that is easy to machine and cheap.