The Hillman Group 2511 1/4-20 x 5/16 x 3/4 Inch Brad Hole Tee Nut, 13-Pack

I made a kid's desk so that it could be collapsed mostly flat for storage or shipping. Comes apart and puts back together needing only a phillips, and there is an electric screwdriver stored under the floor for doing that. all 1/4 machine screws go into hidden t-nuts like this or like that, which come in through the other side of the board to prevent failure. Hardest part was coming up with removable decorative trim to hide all the hardware, but its made easier on a kid's desk where some whimsical carvings or insets do not look out of place.