Slat-Built Modern Coffee Table (w/ Additive Joinery)

This table is a really fun and simple build. Easy, but quite a bit of work. It requires accuracy and patience, but with those two traits, ANY intermediate and most beginner woodworkers can build this.

If you want the MOST in-depth instructions, check out the build video included in this guide. Everything will make a lot more sense after you do, though I'll do my best to fully explain every step along the way.

MATERIALS:
- Wood: Hardwood of your choice is recomended. 3/4" thickness is best because it can save you a step. You can easily use plywood if you keep the striped or "grain" side as your 3/4" side. I have never tried softwoods for this type of build, so feel free to try, just don't blame me if it falls apart.

- Wood Glue

- Pneumatic nailer/hammer and wire brads 1.25" length is best, 1" is the minimum. 18 gauge or thereabouts recommended.

- Table Saw: If you don't have a table saw, you can use any capable saw you are comfortable with that can accurately cut your boards into strips, lengthwise.

- Miter Saw: or any saw you're comfortable using that is capable of accurately cutting a 31.6 degree and 90 degree angle.

- Measuring tape or device

- Clamps: Not entirely necessary if you're using nails, but something like a few bandiclamps, or longer bar clamps for the later stages will eliminate nail holes on the front of your piece.

- Sander: belt, random orbital, hand, just make sure you have a rough grit (like 80), a medium grit (like 120) and a fine grit (like 220)

- Finish: I used an oil/wax combination, but choose what works best for you!

Understanding the design of this build will really help in the process. I've broken down the design and construction into what I call "additive joinery." That's when, instead of removing material to create a joint, you build the joint together out of smaller pieces. Each panel (or side) is made up of strips, the ends of which are staggered to create additive "finger" joints on the end. The legs have additive dados created in the same manner. it is designed to be able to be built using as simple tools as possible, and with lumber that is widely available.

I often call this design, where the surfaces of the table don't fully meet, an "impossible" table, due to comments I received about how fragile and unusable it'd be. It is deceptively strong, however, using the weight distribution of the legs and strong joinery at the corners to displace weight to there it's strongest.

NOTE: In this guide, when I refer to a "trapezoidal" cut board, I mean one with sides that are NOT cut parallel, like Side A in the diagram. When I refer to a "parallel" cut board, I am referring to one that is, like Side B.

So let's get started

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CUT LIST : (all measurements are from the shorter lengths of the slats, all angles are 31.6 degrees)

Side A

- 17.3125 (17 5/16)" x 1" x .75" Trapezoidal cut slats (11 total, make a couple extra)

- 18.5" x 1" x .75" trapezoidal cut slats (12 total, make a couple extra )

Side B:

- 12.75" x 1" x .75" Parallel cut slats (23 total, make a couple extra)

Side C:

- 6.75" x 1" x .75" Trapezoidal cut slats (23 total, make a couple extra)

Side D:

- 12.75" x 1" x .75" Parallel cut slats (23 total, make a couple extra)

Side E:

- 14" x 1" x .75" Parallel cut slats (23 total, make a couple extra)

Side F:

- 12.75" x 1" x .75" Parallel cut slats (23 total, make a couple extra)

Side G:

- 9.8125" (9 13/16") x 1" x .75" Parallel cut slats (12 total, make a couple extra)

- 11" x 1" x .75" Parallel cut slats (12 total, make a couple extra)

Leg part H:

- 21.5" x 1" x .75" Parallel cut slats (4 total, make a couple extra)

Leg part I:

- 10" x 1" x .75" Parallel cut slats (4 total, make a couple extra)

Leg part J:

- 10.25" x 1" x .75" Parallel cut slats (4 total, make a couple extra)

That is a total of 2190.5" (182.54') of 1"x.75" slats, not counting any extras. So when you're buying your lumber for this project, plan accordingly.

1. On your table saw or other capable tool, measure, mark and cut your lumber into 1" wide slats that are .75" thick.

2. I had some old finish on mine, so I planed that off. MAKE SURE that if you do this, ALL slats remain 1" x .75" afterwards.

3. Keep a copy of the cut list from the previous step nearby. Use your judgement when dimensioning your lumber to get the most out of each board.

1. According to the cut list, cut each piece to it's final dimensions. Remember, every angle is 31.6 degrees.

2. It helped me to gather all of each side's parts together in a pile while cutting them.

3. I made a simple stop block by nailing a board at the appropriate length and angle necessary for the majority of the cuts. It helped with accurate repetition.

This is a jig I made to help me align the first panel correctly and accurately.

1. It's simply an extra cutoff of STRAIGHT wood nailed to my bench, with a 1.1875" (1 3/16") cutoff of a slat that had one 90 degree side and one 31.6 degree side.

2. the 1.1875" piece is attached at a 90 degree angle to the first piece, and has the shorter side facing upwards

3. To use it, place the longer "Side A" slats next to each side of the 1.1875" piece

4. Slide the shorter "Side A" slats down over the 1.1875" piece, between the longer slats

5. Attach the three slats and continue in series.

- Note: be careful with your alignment here, It is VERY important to get everything as accurate as possible. Also be careful with whatever glue you use along with this jig, as it IS made of wood and will absorb glue and become unusable.

1. Arrange the slats to one side is PERFECTLY evenly lined up and the other is staggered or "toothed," as shown. Use a slat from Side B to check the depth of your slots here, before gluing.

2. Spread wood glue evenly over the adjoining faces of each slat.

3. Either attach each slat as you go with a few nails OR use clamps to glue up the entire panel at once.

4. BE SURE to check your alignment and measurements as you go. This first panel is the building block for the entire table.

5. Let the glue set or fully cure before moving on to the next steps.

1. Spread glue over the bottom 1" of the 1" faces of one of your 12.75" "Side B" slats.

2. Insert it into the first "full" slot (not the edge one) in your "Side A" panel. MAKE SURE the bottom end of the slat is COMPLETELY FLUSH with the bottom side of the "Side A" panel slots.

3. Affix it with nails. I used two 18ga wire nails to ensure it wouldn't rotate out of place.

4. Glue the bottom 1" of another "Side B" slat, but only the one side that will be touching the outside edge slot

5. Insert it into the edge slot as pictured

6. Affix with nails

7. Glue the 1" sides of another "Side B" slat where it will be touching the others, once slid in between them.

------------------ OK, from this point on, if a part of a slat will be touching another part, just add glue in between them. I don't think I have to tell you how to use glue on every step. ---------------------------------

8. Insert this third slat in between the first two, and affix them together with nails.

9. Continue adding slats in this fashion until you reach the end of the panel.

1. Just like in the last step, continue the build, panel by panel, using the staggered edge of the previous panel to start each new one.

2. Be mindful of your alignment. Fix as many mistakes as you can before the glue dries. Problems early on will compound themselves later. So long as you are careful, this stage of the build should be relatively easy, it just takes a long time.

1. I did this by eye, but here's where I put mine.

• The legs that end on the "Side A" panel are placed exactly 6 3/8" from the unattached, flush end of the panel
• The legs that end on the "Side E" panel are placed exactly 2 1/8" from the edge that connects with "Side D," measuring from the BOTTOM of the panel.

2. With the top edge of the leg DEAD FLUSH with the top edge of each panel, mark the leg location on the 3/4" side of each panel they cross. Do this for all 4 legs.

If you want to taper your legs:

3. On each leg part "H", mark the location on the 1" outwardly facing side, near the inward facing edge, where the bottom of Panels "G" and "C" would intersect them. This will be used in the next step. Refer to the diagram to see where the tapers are if this is confusing.

4. Mark the same location on each leg part "J"

I used some scrap to make a tapering jig on the table saw. I's very simple and you can see it used in the video and the above pictures. You can also use a jigsaw, handsaw, or any other capable tool you feel comfortable with to add this taper.

1. Measure 1/2" on the bottom edge of your leg parts "H" and "J." Mark this location on the outward facing 1" side.

2. Draw a line from this mark to the one you made in the previous step.

3. Use whatever tapering setup you chose to cut that taper along your mark on all of your "H" and "J" parts.

---ALL PARTS for each leg must be "facing" the same way (keep the sides flush)------------------

1. Add glue to one 1" side of "Leg Part I"

2. Attach it to "Leg Part H" EXACTLY 1" from the top edge. As pictured, you can use the body of the table to help with alignment.

3. Secure it through the unglued 1" side of "Part I" with nails

4. Spread glue on the 1" side of "Part J" that matches with the leg you are assembling.

5. Attach it to "Part H" flush with the bottom (1/2") edge. It should be exactly 1" away from "Part I" on the same side.

6. Secure it with nails through the unglued side of "Part J"

This is only a separate step because I want to remind you to make sure the legs are assembled with the right geometry.

1. Repeat for the remaining 3 legs, MAKING SURE to have a leg that fits each side. There should be two sets of identical legs. these two sets should be mirror images of each other.

---------------NOTE: I made my legs too thick and had the tapers on the outside at first. In the video and some of these pictures you can see that. Halfway through the project I decided that was terrible and put the tapers facing each other and thinned the legs to 1", like I have here in the guide. Sorry for the discrepancies.------------------------------

Now we are going to add one more outer row of slats to each side of the table in order to make it flush with the legs.

1. Gather your remaining slats for each side

2. Place your legs on the body in their final locations, using the marks you made earlier.

3. Mark and cut any slats where they will intersect the legs. Be as accurate as possible. These angles are NOT all 31.6 degrees.

4. Glue and the final row in place, piece by piece, dead flush with the body.

5. IF YOU DON'T WANT VISIBLE NAIL HOLES, use clamps or tape to hold these in place until they are cured. I used nails to affix mine and had to fill the holes in later. I wouldn't recommend it.

Ok, if you're at this step, GREAT! All of the match and measuring is done for. However, if you've not been very careful with your measurements and cuts, then this step will take you a while.

1. Using the method of your choice, sand everything flush and flat, inside and out.

2. I found a piece of scrap wood with a sanding belt stretched over it is ideal for the hard to reach angles.

3. I chose to round over all of the outside angles and corners. Its not necessary, but it could save you from some injuries.

4. Knock down any sharp corners or edges, even in you're not gonna round them over.

- DO NOT KNOCK DOWN OR ROUND OVER THE CORNERS OF THE LEG SLOTS!

We saved this step until now because it's harder to sand with the legs on the body.

1. Add glue to your leg slots on the body. (all three sides)

2. Insert the legs to their corresponding slots (DOUBLE CHECK THIS)

3. Clamp them in place or nail them if you don't care about nail holes.

4. Once cured, knock down the corners of the legs, flush them up, and fill any holes around the piece with sandable wood filler.

-Clean off any and all sanding dust from your piece.

- I chose to use a combination oil/wax finish on my piece. I wouldn't recommend it. You can use whatever you are comfortable with, but I would suggest looking up what looks best with your chosen material. A nice Danish Oil or Tung Oil Finish would work well, as would a clear, satin Polycrylic, if you're stuck for ideas.

- Be sure to follow the instructions for whatever finish you choose carefully. This is the last step, but rushing it could leave you unhappy with your piece.

That's it! At this point you should have a new, modern, coffee table!

If you find any errors in this guide (hopefully there aren't any) or have any questions, feel free to leave a comment. if you build one of these, I'd love to see it!