The Cajón  that also doubles as a children's chair described below was a half-day project that I did together with my 3-year old twins. Obviously the kids can't be anywhere near a table saw, but they enjoyed listening to the loud noise from the garage from the safe distance of the room next door. And since this is a fairly simple project, cutting the pieces doesn't take long enought to bore them, nor long enough for them to run off and do mischief. The twins were fantastic helpers for sanding the pieces, but also a formidable challenge when trying to glue the box together with more-or-less right angles.

The inspiration for the drum I built comes from http://quainpercussion.com/cajon-building/.  I simplified the process by creating a kid-sized smaller version of the drum (without a snare), which meant I could use the fence of my small table saw to get quick and precise cuts. The smaller size of 10 inches was chosen so the kids can comfortably sit on it. It still sounds pretty good, but (most importantly) it's not loud enough to be a complete nuisance.

Here is a list of materials used:

After cutting the pieces we glued them together, using combination squares to check for trueness of the corners, and clamps to hold everything together until dry. I also decided to add wood screws to make the box a bit more tolerant of the rough conditions Eli and Ian might force upon it. (The kids were hammering wood dowels into 1/4 in holes I made into some scap wood while I was placing the screws.)

The result can be seen in the following photos:

Cajón drum Sketchup draft. You can download the SketchUp file from the link at the bottom of this page.

Cajón drum being played by Eli.

Resonator hole on the cajón, which is still unfinished but already has grass stains on it. Will there ever be time for sanding and finishing?

Cajón Version 2: Resonator side. This one is glued, not screwed together.

Tapa side of the Cajón version 2.