Waffle Table Made From a Single 2x4

My local wood club held a challenge to make something out of a single 8 foot long 2x4. This is an annual challenge and my first time trying. My club members are very good woodworkers, Top Winners at local fairs, former President of the American Associate of Word Turners (AAW), and one has their work in the Smithsonian. Competition was going to be fierce, so I planned to make something very unique.

I had this idea of making a 3D version of a Kumiko design that could function as a table. Most Kumiko is 2D so I thought a 3D version would be interesting. I began the design process by using Tinkercad to help visualize the piece.

Well, I obsessed how to cut certain angles and did many test cuts which ended up failing to meet my expectations, in the end I missed the deadline but continued obsessing how to do it.

My wife always complains how fast I can fall asleep at night but I just think about what I want to make and then dream about it which puts me right to sleep. By the time the next 2x4 challenge came around again, I was ready!

Want to see how I did it?

1) 8 foot 2x4

Table & Scroll Saw

Special Home Made Jig that was the key simplify the build

Router

Torch

I had a basic concept of intersecting triangular shapes that cross-crossed so I decided to mock it up on Tinkercad to see how it would look and get measurements. This helped prove to me it was doable and the number of cuts were not so many. Designing this way let me know the maximum size I could make the piece since we can only use one 2x4.

A standard 8ft 2x4 is ~96 inches by 1.5 inches by 3.5 inches. Tinkercad modeling showed that 10 triangles would be needed with 3 struts per triangle which makes 30 struts altogether.

This would make each strut around 12 inches long x 9/16 inches thick x 1.5 inches wide which would mean I would need to cut eight 12 inch boards.

I like working in metric since it is easier to do the calculations, so in metric, each strut would be around 300mm long x 15mm thick x 38mm wide with some room for squaring off the boards and sanding since 2x4 sides are usually curved.

Cool we can add Tinkercad here so you can zoom around it. Click the [ ] to center the model.

So far this is all pretty basic stuff and now just have to cut a 30 (60/2) degree miter angle on each strut to form the triangle.

First, I had to make a jig that would assure consist cuts on all strut pieces or the table would not fit together. This is where I perseverated for a long long time since originally I thought I would have to create a router slopping sled and cut the struts on a 60 degree angle. (Think of it like shoveling snow on a hill.) I got this in my head based on how the Tinkercad model looked (this is what caused me to miss entering the first 2x4 challenge); however, months later, it finally came to me to just make simple half-lap joint. Duh, so simple!

The jig basically firmly locks the triangle struts together in a consistent fashion. Next, I knew the spacing for the top of the table, so I just marked those out and fixed 5 vertical guides (the brown boards in the pic) to a jig and then marked where these guides intersected the triangle struts. Also you need to mark the middle of each board that crosses the half-lap lines (you'll see that in the next step)

But all in all, Genius right? Well, I was proud of myself for coming up with this idea but I'm sure smarter woodworkers would have thought of it faster.

Now with the hard part mostly done, you just cut out each strut along the lines. See in the 3rd pic the half-lap and bisector. BIG TIP: Be sure to mark each strut so you know where to cut the half-lap (i.e., top or bottom part depending on where the strut fits) and how to put it back together. Also it's a good idea to line everything up and sand or file down to make sure everything is consistent.

With all the struts and half-laps cut, you need to cut a spline slot to join the triangle and provide strength.

I used a Japanese wood finishing technique called shou sugi ban (or Yakisugi) which involves torching wood to a char then scrapping it off. I did this on 2 sides of the struts. So nice.

Maybe it's just me, but it was kinda fun to cut the shims to fit the splines for joining the triangle struts. It's like a puzzle. Basically, once you thickness a board to width of the spline gap, you then cut it at a 30 degree angle that meets in the center of the shim.

Next do a test fit and if good glue in the spline but just the bottom struts of the triangle (brown parts) since you need room to assemble the half-laps.

I thought this step would be easy but it was a lot of work to get things fitted snugly. I added each bottom triangle one at a time to the top waffle section and inserted the splines, glued up, and reinforced with a bunch of rubber bands and clamps.

Here I wished I had octopus arms to speed things up but eventually I was able to get it all together.

Just needed to trim off the shims and apply a finish.

Turned out Pretty Pretty Pretty Cool don't you think. I really liked the top part being light and the sides dark.

Maybe next challenge I'll add more triangles and make a chess board -- maybe chess pieces too :-)