For holiday related reasons, I wanted a gaming table that could be put on top of the dining table, but folded away when not in use. I enjoy origami, and a challenge, so I aimed to make one that would fold small enough to be stored up and inside the table’s frame. Some thought went into hinge directions and how to make the cantilevers stiff, but nothing heavy duty since I was restricted in the folded up shape.
Gaming tables come in many sizes, but respecting the size of my living room we’ll stick to the 4 foot square option. This is a dirty, easy build with cheap, quite heavy material. It took about 4 hours spread over two weekends. If you are interested in other options, there’s a discussion at the end.
Ingredients:
- Plywood sheet, cut down to 1220mm square (or a little over, for sanding). I bought a 5.5 x 1220 x 2440mm sheet and split it with a friend.
- Piano hinge, 3m of
- Bolts. I used M4 5mm screw bolts (recycled out of a meccano set).
- Tools: something to cut the boards down, I used a sawzall.
- Tools: metal hacksaw or dremel to cut the piano hinge down.
- Tools: chisel and mallet to cut the rebates.
- Tools: a 3.5mm wood drill bit and drill/dremel/brace for it
- Tools: screwdriver for the bolts.
1. Cut the wood down to 610×305 rectangles. They will be laid out like the below:
2. Cut the Piano hinge and lay out and markup where to cut the rebates to make 4 book like pieces.
I found drilling the holes first easier, and tried to make the rebate half the depth of the closed piano hinge. Some of the cheap plywood had flaws, so where a drill hole hit a flaw, I tried to avoid fixing a bolt there later.
My 5.5mm thick board had 4 plys, so a single ply was 1.375mm thick, which is roughly half the depth of the closed piano hinge, which means it all sits flat and minimises stresses on the plywood when open or closed.
3. Mount the piano hinge in the recess, and screw the bolts in. Since I’m using cheap bolts that are not countersunk, I use every other hole. This means when folding closed the bolt tops don’t clash. These hinges will be on the bottom of the final sheet.
4. FLIP the whole thing over and repeat for the piano hinges in blue.
I repeat. FLIP the whole thing over.
If you can, and have access to power tools, it’s quite good to get a little overlap between the free edges marked in green. I sanded the overlap to a 45 degree slope on both, so the panels sit flush and tight at the table. The two shortest blue hinges carry the biggest forces, so do them last when you are confident and happy with the process.
Other options
I chose the 5.5mm thick plywood because my local store had it, it was cheap, and even once I’d sunk the hinge in, the remaining ~4mm should be strong enough to not tear out. I’m clumsy, and likely to put a pug of coffee down on the corner, so it being a little heavy suits me. If you spend on better quality plywood, you may be able to get away with something thinner (and it will fold up much smaller and lighter).
I didn’t modify the piano hinge, although to be honest I could easily have doubled the number of fixing holes. The whole thing is relying on the tear out strength of a roughly cm wide strip around each bolt. I may go back and seal the edges of the the plywood with a glue – I’m worried it will slowly delaminate and fail that way.
Metal screw bolts directly into plywood is a brave choice. I can get away with it since the bolts are acting mostly in shear. If I was doing this properly, I’d use Socket Countersunk Sex Bolts, which would clamp the plywood from both sides without protruding or looking cheap. Another option is brass screws through the plywood, and use a dremel to cut them back flush to the plywood on the back. Done right, you could have a nice steampunk style going.
A completely different option would be to use glued felt hinges. This is a nice smooth surface for a playing table, and might be the best option if you are working with very thin light plywood.
Computational methods in Architecture and Origami
If you are interested in the CMA or origami side of the solution, then for your chosen supporting table and unfolded top with real thickness, you are looking to eliminate any mountain fold hinges that align with the sides of the supporting table, and avoid valley folds that do so (these are the two short blue hinges in my design, and a bit of a weakpoint). Ideally, hinges and joints should cross the supporting edge as close to 90 degrees as possible. Parts that cantilever off the table should connect back to as much area as possible.
Working in paper, you can make the green zone a hinge too, but obviously that won’t work for thick stiff materials.
I did look at the Turkish map fold, but it did not get small enough for where I wanted to store the table top : https://www.youtube.com/watch?v=Q3jTZT2e8os The Miura-Ori map fold looks amazing, but requires some very precise angles
I’d be interested to see what ideas other people come up with.
Bakefoldprint 
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