I ended up here after browsing the easycomposites website and thought this looked like a nice forum for asking silly questions!

I am intending to start a CNC build in the next few months and have been struggling a bit with material choice and design of the gantry. A CNC machine gantry needs to weigh as little as possible and be as rigid as is possible, every ten thousandth of an inch is important in determining the precision of the machine.

Most all designs I've seen rely on adding hugely excessive amounts of material to the gantry making it very heavy which introduces other problems that require extra reinforcing of the base & rails and upgrading of motors to work around. Oddly though all the research I do points very quickly to a composite honeycomb design as being by far the best solution for a CNC gantry but it doesn't look as if anyone has ever tried it.

Am I missing something? Are composite designs just so expensive or difficult to do they end up outside of the reach of amateurs, would a composite design be able to withstand hours of vibration everyday and still maintain it's precision?

No problem as soon as I have some tangible results I will send them. I have a few things in the pipeline one of which is a staircase.