Perfectly feasible to build a good machine from wood but not cheaply.! Or easily.

For a Good wood based machine the design needs to be very well engineered and the materials of high quality. MDF just doesn't isn't good enough for this country.

Electronics are the same wood or metal so don't scrimp here.

To be honest if you haven't got metal working tools or skills to weld the frame then I'd encourage you to pay someone to weld it up because it will work out cheaper in the end. Metal is relatively cheap and will cost less than high quality ply woods or man made boards which will be required for any decent machine worth the effort.

Regards the costs, wood or metal then unless your prepared to throw minimum £1000 at it then I'd suggest you leave it alone and save your money. Even at £1k it will be a challenge to build a machine worth the considerable effort required for any decent machine.! . . . . To try and build for less only leads to dissapointment in the end.!