Hello Yuri - Its good to work in plywood. You will need to make it quite a bit stiffer. Use Boxes for the gantry and the columns. Single plane pieces of PW are not stiff enough in transverse bending. Boxes can be stiffer than metal if big enough. There are many very good timber machines in this forum. Look for videos and info on the Mosquito airplane it was made from plywood and was an advanced machine at the time. I'm designing a mast for a large catamaran and it will be plywood and it will be lighter than the carbon fibre version so go for it.. Peter