I had a couple of lack tables that I had stacked on top of each other for use as storage space, but the top one kept sliding off of the bottom one. This print is designed to fix that.
Each corner piece is designed to use 4 4x30mm wood screws to secure it to the top of the table. Its easiest to line up a couple of screw holes by putting it on upside down, then flipping it over and screwing it down properly.
Do note that the lack tables split quite easily, so be careful when screwing into them as they can bulge if you're not careful and the wood splits. Its not the end of the world, but it is something to be aware of if you care about that sort of thing
I've attached the original solidworks file, and a STEP file so you can modify them for your own nefarious purposes
The author hasn't provided the model origin yet.