Hello Lasersolution,
I don´t know so much of mechanics but I think that the key in the use of plywood in building process of cnc machine, is that this material has a strong deformation resistance, it is very stable and it support high presion in joints.

In my case I use plywood because I need to build a cheap machine and the cost relation in a wood frame compared with a metal or aluminum frame is too high.

I think that if the surface is too flat and with the use of the appropiate linear motion system as a SBR16 and BK-BF end supports you can optain a really good quality in the movements and high presicion in all the parameters.

I hope that this week I can do my first probes with the new cnc machine that i am buliding,, and I would to chare with you the results of that probes,,,

I am interest in your opinion and see you next days for more information about.

Macsim.