Turn an Ikea HOL coffee table into a stackable, side-opening storage cabinet

Step 3 Trim 1/2" off the internal baseboard

Cut about 1/2" off the internal baseboard inside the HOL. The baseboard is the horizontal, almost-cardboard-like particleboard bottom to the HOL unit. It wants to slip into a slot in the side that you want to use as a fold-down, and that will prevent your desired side from folding down, so you need to trim the baseboard back. Again, normal saw or SkilSaw, or even a table saw, will work fine for this. While you're at it, you might want to cut a hole for power cords in the baseboard if you want to put anything electrical in your new shelf.