Joiner for IKEA LACK tables

These joiners let one IKEA LACK table sit on top of another securely.  The cross-shaped peg makes a solid connection and ensures that the table legs won't rotate.  The tables are not fastened together; you can lift the top one off at any time, and the leg part sits flat on the floor.

I designed this using Fusion 360.  I've included the .f3d and .STEP CAD files in case you want to modify the design.

Print Settings

I used PETG.  PLA would also probably work.  Default settings and a coarse layer height are fine.

Assembly

Print four each of the upper and lower pieces.  Print one each of the table and leg drill guides.  You will also need 32 #8x2" wood screws.  (If you know the metric equivalent, please leave a comment, thanks.)

Use the drill guides to mark where to drill holes in the bottom table and in the bottom end of each leg of the top table, as shown in the photos.  Then drill holes, screw the parts on, and build the tables.