Space Saving Expandable Table for Tabletop and Board Games

We needed a table for playing board games. We were using our dining room table, but we always had to cut games short, or starve. No problem, time to build a table! However, we like to play miniature games that require a four-foot square table. Well, that kind takes over a room. OK… still no problem, just expand the table when needed and shrink it when not! Originally, we thought of making a table where you can take leaves in or out, but then they have to be stored. How about a table where the sides fold down? They’re not that functional when small; you can’t sit and tuck your knees under the sides. We wanted a usable table when big and small! Since the answer was non-obvious, I naturally turned this into a challenge with my kids - best idea gets ice cream! I sauntered off, trying to decide just what flavour I will be enjoying.

The next day, one of my sons bounced into my office with this:

“Hey dad, I have an idea. Instead of leaves that fold down, we have them fold up to make a second tabletop! If the leaves are four right isosceles triangles with the hypotenuse along the table’s edges, we could unfold them to double the surface area of the table.”

Whoa, my kid just said what now? (and well-done Ontario teachers). But he wasn’t done there.

“If we rotate the tabletop, but not the table legs, the legs will stick out and we can unfold the triangles leaves and have them supported by the table legs. Will that work?”

“Ugh”, I said. “I’m not sure how we’ll do that, but to support the leaves on the table legs, they need to rest at half the height of the triangles. Why don’t you go run the numbers?”

“OK, thanks Dad.” Out the door he went, and with him my double chocolate, peanut butter swirl, with marshmallow ice cream cone sailed away.

Not long after, he returned.

“Dad the table legs go out 94% of the way there.” (Did I say bravo to his teachers yet?) “Hmm, let me see your calculations.”

He was right on, and this design was Officially A Go!

4 - basic table legs, black (https://www.leevalley.com/en-ca/shop/hardware/table-hardware/legs/legs/72628-tubular-steel-table-leg)

1 - 4’ x 8’ x ¾” finished on both sides plywood (https://www.homedepot.ca/product/araucoply-premium-pine-plywood-acx-3-4-inch-x-4-ft-x-8-ft-/1000119483)

1 - Chicago Bolt, brass (https://www.leevalley.com/en-ca/shop/hardware/fasteners/nuts-and-bolts/40051-chicago-bolts)

8 - Card Table hinges, brass (https://www.leevalley.com/en-ca/shop/hardware/table-hardware/extenders-and-leafs/40208-card-table-hinges?item=00W2301)

1 - Round Campaign-Style Ring Pull, brass (https://www.leevalley.com/en-ca/shop/hardware/pulls/ring/73173-campaign-style-ring-pulls?item=00A1822)

51 - #7 ½” Brass Screws, I got mine from a specialty shop with no online links (Sorry!)

1 - 4’ x 8’ x ¾” OSB sheet. OK, I went with this because a neighbor down the street has just finished laying sod for his yard and the chipboard was out for the taking. I say SCORE! My wife… not so much. Luckily, it cleaned up nice-ish, a thick layer of paint hides many things!

Black Paint (I hear it hides many things)

Golden Oak Stain (https://www.canadiantire.ca/en/pdp/minwax-wood-finish-0480700p.0480847.html)

Expresso Stain (https://www.homehardware.ca/en/946ml-espresso-alkyd-wood-stain/p/1872453)

Clear Diamond Hardening Stain, to protect the surfaces (https://www.homedepot.ca/product/varathane-diamond-finish-premium-diamond-wood-finish-for-interior-water-based-in-satin-clear-946-ml/1000111893)

Tools:

Table Saw

Chop Saw

A busted old circular saw (yeah there’s a story here, we’ll get to it)

Jig Saw (that should have been a working circular saw)

Router, fixed and plunge (if you don’t have a plunge router a hole drill bit and patience will work)

Cordless Drill with screw bits and drill bits

Paint and stain brushes.

(optional) calipers

(optional) gold metallic permanent marker

Being my first furniture piece, I wanted to keep it simple and affordable. So off to Home Depot to buy the most affordable full sized 4’ x 8’ x ¾” finished both sides plywood. You can use any suitable material you’d like, but it needs to be at least ¾” thick to accommodate the hinges and ring pull.

Based on the dimensions for my table in its unfolded state (4’ across), each leaf needed to be 2’ per side so their hypotenuse turned out to be 33 and 15/16” (thanks Pythagorean). This made the tabletop 33 and 15/16” per side. You can scale your version as needed.

On paper, I drew out a scale version of all the pieces for the plywood so I could experiment with their placement to see the best way to arrange my cuts. And hopefully get some useful extra pieces. One thing to keep in mind is the blade kerf. Two leaves next to each other are 4’ across, but I couldn’t place them along the 4’ width of the plywood because the blade will eat up some material leaving the leaves less than 2’. I had enough room to cut the tabletop and all four leaves with some extra.

With the cuts planned, it was time to transfer the measurements to the plywood. I used a 4’ straight edge and a 2’ square.

I decided to do a rough cut for the tabletop on the table saw, then trim it down (still on the table saw). Trying to get an accurate cut in one pass with that much extra material to deal with didn’t seem like a good idea. I’ve awarded this piece “Best Cut of the Project.” NAILED IT! To the millimeter! (that’s almost to 1/32”!!!) If only all my cuts came out that good…

I decided against using the table saw for these angled cuts. I got out my trusty old circular saw and made guides out of the 4' long ruler and some clamps. The only problem was that the circular saw was big on the “old” and lacking on the “trusty” – more like it broke before a cut was made. It has been sent off to a lovely retirement. What now? Well, I still had my trusty old jig saw! Of course, in retrospect I should have bought a new circular saw.

With the straight edge clamped and careful cutting I did make it work, but it took a lot more time and more fiddling that it should have. But eventually the tabletop, and four leaves were cut, and test fit together. For your build, I wouldn’t suggest a jig saw. Stick to a circular saw or make it work with a table saw.

Since the tabletop needs to rotate 90 degrees before the leaves are unfolded, you’ll need a pivot. I decided to use a Chicago Screw.

If you’re not familiar with Chicago Screws: the one I bought is essentially an elongated nut with a flat head at the end. The nut is smooth on the outside and threaded on the inside. It’s paired with a short screw which has a matching flat head on the end. The flat heads rest on the pieces to be fastened. When the screw is tightened, the two pieces are squeezed together. With the proper length of nut chosen, this arrangement will allow the two pieces to rotate but not separate. Depending on the thickness of the material you use, the length of the nut may not seem to fit, but worry not, if you get a set that is too long you can always put some washers on the bottom to get the right fit.

Ever get caught up in a great idea, and kind of gloss over some of those important details? Not just me, I hope. I knew I was going to use card table hinges, and a Chicago Screw as the rotating pivot. I didn’t really think through how I was going to attach the table legs to the pivot. I’m calling my design for this part the leg sub-structure. I decided to make an 'X' pattern with the legs at the ends and a small square in the middle, which would hold the Chicago Screw. In the end it looked like the picture above.

I was afraid that making a full square undercarriage just to attach the legs would have too much friction and make it hard to rotate the tabletop. This little gem of a decision gets the "Razzy" Award for forgetting that building a great big 'X' for the legs also makes the table wobbly. Ah hindsight, where were you when I needed you? Anyway, with plan in hand it was time to get building. This did turned out to be a pretty good design. For your build, I’d probably suggest using a full square on the bottom and maybe router out some material if there’s too much friction with the tabletop.

Starting with a 4’ x 8’ sheet of OSB, cut a small 16” square of OSB. The plan is to screw the OSB 'X' to this square.

Then cut four 34” x 8" strips of OSB for the ‘X.’ Make two 45 degree angle cuts into all the ends (you’ll see why in a minute).

Curious about those cuts? I did them at one end so they match the corners of the table (this is also the end where the table legs will attach). Take a look at the picture above, I made sure the table leg plate would fit before I made the cuts. At this point you can go ahead and attach the four table leg plates. I did wait until later but it’s up to you.

If you’re wondering what a table leg plate is, either you’ve never used this kind of table leg, or I just made that term up, I’ll leave it to you to decide. The leg plate fastens to the bottom of the table and has a bolt that sticks out for the table legs screw into. The above right picture shows what the plate looks like when it’s attached.

OK so why the 45 degree cuts on the other side? I did this so these pieces would fit neatly together, however they fit so well together that there wasn’t any room for the Chicago Screw! I cut the tips off the ends to make room for the screw.

You get the “Most Observant” Award if you noticed that the Chicago Screw isn’t brass; that was a last-minute upgrade I made. You’ll see it later.

At this point, I have to confess I had just got a new cordless drill/driver, which explains the excessive use of screws to attach the 'X' to the square.

Of note here: What you are seeing is the bottom. I wanted to attach the screws from the bottom up, just to make sure none of the screw heads would touch the tabletop. It was at this point that I attached the table leg plates.

I found the exact center of the tabletop, clamped it on the leg sub-structure (with all the corners lined up) and drilled a pilot hole through both the tabletop and the OSB square. This way the tabletop will rest on the 'X' of the leg sub-structure but the pivot connects the tabletop and the bottom OSB square.

Then I drilled the correct diameter hole for the Chicago Screw. Lastly, using a bigger drill I counter bore the hole in the tabletop so the screw would sit flush on the table.

For your build, I don’t recommend using OSB. Even though you’ll only ever see it when you spin the tabletop to open or close it, it’s not the best look. I would recommend replacing it with nicer plywood.

I decided to use Card Table Hinges from Lee Valley. They’re built so that they can only open 180 degrees, and they are double hinged so when the leaves fold over, they will rest flat on the tabletop. Very cool!

There are a few points of concern for working with these hinges, in this design:

Each leaf has two hinges. If they aren’t at 90 degree angles to both the table edge and the leaf edge, I don’t think the leaf will open nicely.

For the leaves to run parallel to the table edge each hinge had to be flush with the edge of the tabletop, and leaf. Having the hinges flush is also necessary for the four leaves to close snug against each other to form a square top.

High on my list of new tools to buy is a good router. Why? Because for this build all I had was a Dremel with a little router attachment. I got a nice bit and it worked well, but it did take some time.

First, I did some test routing on some scrap cuts of the plywood, you can skip this step if you are familiar with routing plywood.

As all the hinges will be visible when the table is open, it is important to get the routing right.
This is definitely a “measure twice, cut once” kind of operation. To make it even more *fun* the hinges require two cutting depths; one for the face plate, and a deeper cut for the hinge mechanism. I started with marking and routing out the tabletop. That way you can place all eight hinges uniformly on all four sides. Never having done something like this I took it slow and did a lot of test fits.

With all the routing done on the tabletop, line up and mark the hinge locations on the leaves

I turned the hinges upside down to trace their outline on the leaf. With all eight hinges routed out, it’s time for the first test fit. Overall – I got it, they fit nicely together. Snug, I might say, but definitely functional. I didn’t screw the hinges into place yet; the screws are small and I only wanted to do it once, after sanding and staining. I recommend marking which leaves go with which table side. I marked letters where the hinges will cover. That way, I wouldn’t touch any part that will be visible when finished.

Now, one of the details I did think of was how to open up the tabletop. I needed to have some way to lift those leaves up. I decided on a ring pull as it would sit flat, look good, and not be too big. I toyed with the idea of using four ring pulls to get a uniform look, but I decided against it because of the costs.

As with the hinges, there are a few points of concern for working with the ring pull:

It will be visible, so the routing needs to be done right. It should be a tight fit as well as sitting flush. If the pull sticks above the tabletop it will mess with our board games!

The ring pull is ½” deep and the leaf is ¾” thick. That’s not a lot of room for error.

The pull needs three routing depths, one for the faceplate that will screw to the leaf, one for the swing handle mechanism, and one for the body of the ring pull.

Remember me talking about needing a good router, well make that a fixed and plunge router.

I clamped the tabletop and leaves together, then eyed out the right location for the pull.

Using your plunge router will make quick work of this step. However, only having the “Little Dremel that Could,” I started by drilling a shallow pilot hole. Then I upped the diameter with a hole saw. I worked away with a drill bit until there was a shallow hole that was big enough that I felt comfortable using the Dremel bit.

I repeated the above for the deeper, narrower cuts. Slow, steady, and lots of test fits. In the end I used calipers to measure the depth, and eventually I got it. Since this Ring Pull will be a focal point when the table is closed, I spent the time to make sure it was a good fit.

This is a personal choice, but since this was a table that was going to expand to double its surface area, I decided to have two stain colours. A darker colour for the closed, space saving size, and a lighter colour when the table is all folded out. What about the transition from the light side to the dark side you ask? (there’s a great Star Wars joke waiting to happen here) A few matte black coats of paint would tie the top and bottom together. Now being colour blind, when it comes to these decisions, I consult with my wife. She loved the idea and got the perfect colour stains. Then she kicked me out of the garage so she could do it, sand, stain, and paint.

For sanding, the top and bottom surfaces of the plywood only needed a quick go-over with a fine grit. The sides and routing edges needed a bit more attention. We used a medium then fine grit paper, and slightly rounded the corners, just a little bit.

When it comes to staining, my wife (remember I was kicked out at this point), used clean rags dipped in well stirred (never shaken) stain. After dipping the rag in the stain, she pushed the rag from bottom to top, making sure to only go in one direction. This results in a nice even stain.

“We” started with the light oak on the table, and one side of the four leaves. Once we had two coats of coloured stain and two coats of the diamond hardening stain done and dried, we could stain the other sides with the expresso (and hardening) stains. The diamond hardening stain helps protect the soon-to-be heavily used surface. We also stained the underside of the square table. Why? To protect the bottom, and if you ever have to crawl under the table to get a game piece, the underside will have a beautiful, unified look (maybe I’m going too far here? – Nah!)

With the staining all done it was time for black paint. Any visible OSB was painted black, and it took a few coats to look OK..ish. We taped around the table legs; they were black enough. Then we painted the top and bottom.

Last painting step is to paint the sides for the tabletop and leaves; two thick coats hide most of the layers of the plywood.

You need to watch out for paint getting on either side of the tabletop or leaves. We had a clean rag at the ready to quickly wipe up paint that ended up on the top or bottom. When you’re building your version stay right-on this step. You don’t want to blemish the surfaces.

It’s go time! With all the parts stained, painted, and dried,

it’s time to bring the pieces into their place of honour.

Attach the legs to the frame.

Place the tabletop on the leg sub-structure and attach the pivot.

Screw all the hinges in place.

An extra cool feature – I added a gold (how luxurious) marker line across the leg sub-structure as a visual indicator of when the tabletop was spun to the correct position. The idea is that when you want to open the table up, you spin the top until the edge lines up with the gold line, then you know you’re in the right position to unfold the leaves!

Last, but not least (if you ever want to open up the table that is), fasten the ring pull.

Success! My first piece of furniture is done.

Test by playing a lot of games juuuussst to make sure it really works. I had a lot of fun, and learned some new skills making this table. By the way, my son will enjoy my double chocolate, peanut butter swirl, with marshmallow ice cream cone very much. Thanks.