I modded the leg connectors from the Prusa printer enclosure parts to stack an additional table on the bottom without walls. Makes a nice stable table stacking coupler for other purposes as well. I attach them with #10 x 3/4" wood screws and a little glue to keep them from rotating after they are attached. Works great.
Check out these other things for IKEA Lack table...
Table leg levelers: https://www.thingiverse.com/thing:3495732
Leg stiffeners: https://www.thingiverse.com/thing:3490946
bottom_table_leg_end.stl | 107.8KB | |
bottom_table_nipple.stl | 90.9KB |