Foldable magnetic chess board with hidden space for bottle. Made out of WOOD-PLA, PLA, screws, hinges, steel plates and silicon glue.

Print settings

Printed on Creality K1C 0.4 nozzle
0,24 layer for boards, 0,1 layer for pieces, everything else on 0,2
Magnets are inserted during the print. I used 10mmx3mm round magnet from AliExpres (they're too strong though).

Print process

Print Board_R.stl, Board_L.stl, Board_R_kings.stl, Board_R_pawns.stl, Cover.stl and Board_R_shelf.stl (this twice) out of WOOD-PLA. Use supports if necessary.
Print Surface.stl twice out of WOOD-PLA. Make the top surface pattern "hibernal curve" or similar to make rough surface (for glue).
Make a hole from bottom into Bishop.stl, King.stl, Knight.stl, Pawn.stl, Queen.stl and Rook.stl in your slicer. Example: hole 10,3x3,5 mm and than add cylinder 12x0,4 mm.
Print Bishop.stl, King.stl, Knight.stl, Pawn.stl, Queen.stl and Rook.stl. Right before printing of 35th layer (or higher/lower, if you set different layer size) pause the print, add the magnet and continue the print. I printed out of generic black and white PLA.
Print all Stencil0.stl - Stencil7.stl out of any cheap PLA. Stencils are for purpose of spraying.

Painting process

Only the bottom part (the smooth side) of Surface.stl is being painted/sprayed.

I used 2 layers of primer for plastic materials on whole bottom surface. Leave 30 minutes before 2nd spraying and 1 hour before paint spraying.
Apply printed stencils to Surface.stl by taping it and putting heavy objects on the top.
I used 2 layers of glossy brown colour for plastic materials. Leave 30 minutes before 2nd spraying. After 2nd spraying, remove stencil immediately. Don't use all the stencils at once. Use tape or rags to cover exposed part of Surface.stl which shall not be painted.

Assembly

Find yourself steel sheets <1mm thick and cut them, so they fit into Surface.stl, Board_R_kings.stl, Board_R_pawns.stl. Glue them to the mentioned parts. I used MAMUT silicon glue. Tighten with clamps.
Glue Surface.stl with metal sheet to Board_R.stl and Board_L.stl. Be careful not to scratch Surface.stl.
Glue Board_R_kings.stl and Board_R_pawns with metal sheets to Board_R.stl. This part will serve as a shelf for pieces when the board is folded.
Find yourself (or 3D print) hinges of proper size and screw them to Board_R.stl and Board_L.stl.
Insert bottle of a proper size to Board_L.stl and slide in Cover.stl.
Insert pieces into shelf of Board_R.stl and close the board. If you have difficulties to close the board or keep the board closed, use hot air gun to deform closing teeth.

Conclusion

I apologise for making the process difficult and imperfect. I have been using the chess board for over 2 years and I'm frankly satisfied with it. Nevertheless, I wish it would serve to you at least as an inspiration.

Chess board with bottle hide

0.2mm layer, 2 walls, 15% infill