Quote Originally Posted by pippin88 View Post
Why put a steel skeleton inside?

If the steel is for stiffness it is better to put it outside. Material at or close to the neutral axis does very little for stiffness.

Save the money you would spend on laser cut steel and put it into more epoxy granite for bigger sections.
Are your sure about that ?
Sure I'll put steel outside for screwing and rails, ballscrews .. etc.
Epoxy granite alone is that stiff for a large machine ?