Introduction: Hardware-free LEGO/DUPLO Table (IKEA LACK Hack)

When I first began writing this Instructable, my oldest son (aged 3 at the time) had an incessant desire to build with DUPLO blocks. His sister (aged 2) loved playing monkey see, monkey do and following her brother's every example. Most days, DUPLO were the first and last toys they played with. I couldn't help but notice just before Christmas that year that they were spending a lot of time crouched down on the carpeted floor building away, quite often arguing over blocks and build space. This got me to wondering how I could possibly provide them with a better area to build that would also be conducive to cutting back on the amount of bickering over space and blocks. It was just a week and a half before that Christmas that I decided to go all "Santa's Workshop" on the situation and build them a table that they could work at as a Christmas gift--a gift that would NOT be from Santa, but instead, from mom and dad...because the best parenting pro tip I have ever received is that the best Christmas gifts always come from mom and dad, not Santa!

Since the initial draft of this Instructable, my kids have aged (now 5, 3, and another at 9 months old). The building craze has expectedly taken a turn to LEGO, and this project too, has shifted and evolved. My 9-month old boy conveniently began crawling and teething right at the beginning of the Coronavirus shelter-in-place, and my older two have decided the floor is the best place in the house to build LEGO. Not a good combination of variables. I had to (very quickly) come up with a solution that accomplished some different objectives:

  1. I didn't want to totally scrap the DUPLO design, so I kept some of that intact for my youngest when he is of age to build DUPLO.
  2. I had to create elevated build surface for LEGO for my older two, who enjoy being around each other while they build.
  3. Provide a "change of scenery" for my kids since they were going nuts because of the shelter-in-place.

I took my original design of the DUPLO table, made some quick and easy modifications to the Fusion360 couplers in TinkerCAD, and quickly had solutions to my objectives.


There is no hardware required for this project! You will however, need to 3D print the couplers.

For this build, you will need the following materials (linked out for you):

  • (3) IKEA Lack Side Tables (IKEA)
  • (4) Large Baseplate, 10 in x 20 in (Amazon)
  • (2) Dry Erase/Chalkboard Sheet, 0.118 in x 24 in x 36 in (Lowe's)
  • (1) Scotch Indoor Mounting Tape (Lowe's)
  • (1) Cowles Door Edge Molding (Auto Zone)
  • (8) 3D Printed Table Foot (Thingiverse)
  • (2) 3D Printed Upper Coupler (Thingiverse)
  • (2) 3D Printed Mirrored Upper Coupler (Thingiverse)
  • (2) 3D Printed Lower Coupler (Thingiverse)
  • (2) 3D Printed Mirrored Lower Coupler (Thingiverse)
  • Fine grit sand paper

For remixed versions of this project, and for different table styles (see images) you will have to use some different couplers to connect the IKEA LACK tables. Modifications to the couplers listed above can very easily be made in TinkerCAD using the plane and hole tools to create your own remixes of the table. I will show you how at the end of this tutorial in the "bonus tracks".

Step 1: Designing and Printing Parts

In prioritizing my time on this project, I figured it was probably best practice to get my couplers drawn and printing so that I could be working on other parts of the project while the printing was happening.

Measuring Tables for Fitment

While I don't trust everything on the internet, I was able to quickly find enough information on leg sizing to get started on drawing/modeling the couplers. I used my trusty digital calipers to confirm the numbers online were correct, and got right to work.

Recognizing Shortcomings of TinkerCAD

I began my drawing/modeling process in TinkerCAD. While it would have worked okay to draw each of these parts, I quickly realized that it lacked some of the capabilities I needed for the project. The main functionality that TinkerCAD is currently lacking is the ability to fillet, or round off selective hard corners and edges (this is possible when using polygonal prisms, but not for click-and-select edges). This was an important aspect in the design, because 3D printed right angles can be sharp, and I wanted to avoid any possible injuries to my kids.

Designing Parts in Fusion 360

Taking the same measurements and design approaches I was using in TinkerCAD, I began re-drawing my parts one at a time in Fusion 360. The parts were built from a series of different, simple 3D shapes joined together--cubes, rectangular prisms, and triangular prisms. As each separate shape for each of the parts was created, I would print a small segment (or "slice") to check for proper fit onto the leg of the side table or the dry erase sheeting. Once the fit tolerances were set and each part was completed, I filleted all of the hard corners and edges so that they were nice and round. I usually wait to fillet my edges until my design is final so that I can easily take measurements of lines in Fusion360 when needed.

Slicing Parts in FlashPrint

I use a FlashForge Finder at home, so FlashPrint is what I used to slice the parts (it's FlashForge's slicing software). I wasn't worried about high resolution prints for aesthetic reasons, so I sliced these parts at a low resolution (0.30mm layer height) with a 2-shell perimeter, and a 3-layer top and bottom at 15% infill to save on some time. As shown in the images above, the upper couplers were taller parts, and their print orientation required support material (linear at 1.5mm pillar size touching only the platform) as shown in the slicer screenshot, so they took a bit of time to print in comparison to the other parts. The only parts needing support material were the upper couplers. Once I had printed two of each of the couplers, both upper and lower couplers had to be mirrored in FlashPrint to provide the right combination of guides to accept the sheet paneling that will create the center box of the table. After mirroring each coupler in FlashPrint, I printed two copies of each of the mirrored couplers. At this point, I had a total of eight couplers (four upper, four lower) and eight feet.

Printing on FlashForge Finder

Once the files are sliced, printing is pretty straightforward. The filament and time estimations for each part are as follows:

  • Single Foot: 1.5 hours, 11 meters (32g)
  • Single Upper Coupler: 5 hours, 31 meters (91g)
  • Single Lower Coupler: 3 hours, 18 meters (53g)

Step 2: Assembling the Side Tables

The Ikea Lack side table has to be one of the easiest, quickest pieces of Ikea furniture to assemble. The instructions are literally a single page. You simply start threading the double-sided screw provided in the hardware package into the pre-drilled pilot hole on the underside of the table top. Once you have it as tight as you can get with just your fingers, you can use the leg to turn the screw the rest of the way in by guiding the standing screw it into the pre-drilled pilot hole on the end of a leg. Tighten down until firm and square with the table top.

Step 3: Ripping the Box Panels

The cut list for the side panels that create the middle box is short:

  • (4) Dry Erase/Chalkboard Sheet @ 15-3/4" x 17-5/16"

To rip the panels to size, I used a table saw, keeping in mind that the trough of the saw teeth should be flush with the top of the sheet when laying flat on the saw table.

This material actually cut quite nice on the table saw. I wasn't sure of what to first expect, and actually expected some chipping/flaking of the paint on each side of the board, but it was perfectly clean after the cut!

Step 4: Piecing It All Together - ORIGINAL DOUBLE TABLE DESIGN

NOTE: If you want to see how the Double Table, No Box (DTNB) or the Modified with Box (MWB) version go together, please skip ahead to the "hidden tracks" at the end of this tutorial.

This was the most satisfying part of the project--slipping everything together!

  1. Starting with the center table flipped upside down, I added all lower couplers to the legs of the tables. None of the sidewall guides should protrude over the edge of the table top.
  2. Next, I slid the four dry erase/chalkboard sheeting sidewalls into the guides of the lower couplers already installed on the legs of the middle table. The sidewalls will be a tad wobbly until the upper couplers are installed.
  3. The upper couplers were then installed on the legs of the side table and worked upward to the top so that the coupler and tabletop were flush. The legs of the side table were then inserted into the coupler at the bottom of the box and the upper couplers of the side table were slipped over the upward facing legs of the box.
  4. Being very careful to pay close attention, be sure to gently align and slip the corners of the box sidewalls into the guides of the upper couplers, while at the same time fitting the upper couplers over the end of each leg of the middle box.
  5. About halfway through this process, your side table will be hanging in the air--an opportune time to put your feet on the bottom of your outside legs. The feet ensure that the table does not seesaw on a harder type of floor.

At this point, the center "box" has started to take its shape.

The tolerances of the couplers are tight to ensure there is no wobbling of the table when moved around the playroom, so some moderate amount of force may be required to get everything to settle into place.

Repeat the steps above on the other side of the box.

Now we are just a few steps away from finishing!

Step 5: Applying the LEGO/DUPLO Mats

Designing & Printing Mat Spacing Jig

I wanted to ensure that the DUPLO mats were were centered and square on each of the working table tops, so I measured the gap/margin space and designed a mat spacing jig to help with spacing, this time using TinkerCAD because the task was so straightforward and more quickly accomplished in TinkerCAD than in Fusion 360. I used a series of four very flat rectangular prisms all joined together to create a corner. The jig helped align the mats nice and evenly all around the top of each work table.

Application of Mounting Tape to Mat Backs

This was the least calculated step in the whole project for me. What I essentially chose to do was to add double-sided mounting tape around the entire perimeter of the underside of each mat, and then I filled in the space in the middle by simply splitting the difference of the gaps in increments. As I was applying the mounting tape, I was certain to stick it to an area where the most surface area contact could be made, considering the "dimples" on the underside of the mat. I wanted to fill up as much of the space underneath each mat as possible to prevent buckling of the mats when pressing down on them with DUPLO from the top. I also wanted them secured to the table top as securely as possible to keep my kids from getting curious and eventually prying them up. I probably overkilled it on the mounting tape, and I am sure there is a better option out there for adhering the mats to the table tops, but this worked perfectly for me. Be sure to leave the tape backing intact until you are ready to install the mats!

Update: A couple years later, I was able to remove the double-sided tape from the top of each table with no issues, and teach table is being re-purposed now as a lego table.

Using Mat Spacing Jig to Install LEGO/DUPLO Mats

TAKE YOUR TIME WITH THIS STEP! I used the mat spacing jig to install only the first mat onto each of the two work tables, and I will explain why I only used it on the first mat for each work table a bit further down in this Instructable. I made sure that the mat was aligned with the jig in each of the two table corners it was closest to without laying the mat completely flat, so as to avoid total adhesion of the tape to the table top in case I needed to make any minor adjustments. Once I knew each mat was aligned, I removed any remaining backing tape, and set the first mat in place on each work table.

The second mat on each worktable did not require the use of the spacing jig. Instead, the simpler solution was to actually use a couple of DUPLO blocks at the seam of the first and second mats (pictured). This provided a "butt fit" between the two mats that perfectly aligned the posts of the first mat with the posts of the second mat, creating a continuous, useable 20-inch by 20-inch workspace on each work table.

Once all four mats were applied to the table tops, I placed a large board over the mats and weighted it down for a couple of hours to provide constant pressure, ensuring solid adhesion of the mounting tape.

Step 6: The Finishing Touches

The final step was applying the clear Cowels edge molding to create a safer edge on the exposed edges of the center box. The first side I applied the molding to proved a bit difficult--the hard edge of the sheet made application difficult, so for the second side, I decided to lightly sand the corners of the edges away with some fine grit sandpaper to create what was essentially a tapered/beveled edge. I also found it helpful to use a blunt object to open up the channel of the molding a bit too prior to application (I used the plastic handle of a set of small scissors). Opening the channel of the molding and sanding the edges of the sheeting were very helpful in applying the molding, so don't skip these steps--you'll be kicking yourself if you do!

Once I finished applying the edge molding, I took a small hammer and gently tapped along the edge of the molding to ensure it was pressed down completely onto the edge, and to ensure that good adhesion was made between the molding and the sheet edge.

Step 7: Hidden Track #1: DTNB Remix (Double Table, No Box)

This part of the tutorial shows how to create a double table with no middle box. I put this design into action once my older two kids were finished with DUPLO and had aged into LEGO to keep the smaller bricks off the floor and out of reach of my 9-month old.

For this table, some of the original Fusion360 couplers had to be modified. I modified the original STL's from Fusion360 in TinkerCAD using the workplane and hole tools (see first two images).

I modified the lower coupler by "hole-ing" or cutting off the panel retainers. This became the "upper coupler" for this table.

I then made a copy of this "new" coupler in TinkerCAD and added a floor to it to create a coupler foot.

Piecing these parts together is rather self-explanatory.

I am providing the links for these couplers here:

Step 8: Hidden Track #2: MWB Remix (Modified With Box)

This part of the tutorial shows how to create a single table with a sidecar box for DUPLO storage. I didn't want to completely dismantle the DUPLO table I first started this whole project with, because my current 9-month old will be using them before we know it.

Again, like the DTNB Remix, some of the original Fusion360 couplers had to be modified. I modified the original STL's from Fusion360 in TinkerCAD using the workplane and hole tools (see first two images).

I modified the lower coupler by "hole-ing" or cutting off the second leg retainer. This became the "lower corner" for this table. I did the same with the original upper coupler to create the "upper corner". Additionally, I filleted the outside corner of each new component to keep the corner rounded off and safe. You can use this fillet tool as a "hole" on any corner to round it off in TinkerCAD. Simply export it as an STL and then import it into the project you want to round corners on.

This table goes together in approximately the same fashion as the original double table, so follow that tutorial for the construction of this remix, replacing one side of "couplers" instead with "corners".

I am providing the links for the corners here:

Step 9: Changes I Would Make...because...iteration!

As with any design process, this one has been extremely iterative. Here are some things I have decided, or at the very least pondered, to change about my original bare bones design:

  • Include a false bottom in box for shorter kids (pictured)
    • I re-purposed the packing polystyrene from my 3D printer as a base, and some cardboard with notched corners to fit in as the false bottom
  • dividers in box for different types of DUPLO
  • IKEA TROFAST bins under tables (pictured) using these bin sliders
    • It is important to note that there is nothing in the core of an IKEA LACK table, so I used double-sided foam tape and small screws to hold the drawer slides in place
  • Add felt pads to all contact points with floor
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