I studied abroad in Chile last year. One of of my favorite nights we had a music party at our apartment and my musician friends set up a cajon drum and hi-hats in the corner.
Towards the end of the night when the people with talent had all had their turn and everyone was lubricated enough with Pisco to want me to play I took my turn on the Cajon while my two of my friends played nylon string acoustic guitar.
If you have never heard a cajon, it is a surprise how nice what is essentially a wooden box with a snare in it can sound. It is perfect for acoustic performances as it is not too loud. Furthermore, it doubles as a seat. Best of all, they are easy to make.
As I said earlier, you are making a box. Standard dimensions are 12″x18″x12″.
The top and sides are made of 1/2 inch birch plywood. The back is 1/4 inch birch plywood and the front (called the tapa) is 1/8 birch plywood. You don’t have to use birch as any hard plywood works, but birch is the standard as it is easy to find and cheap.
You also need 40″ of 1″x 1″ wood for corner reinforcements. Recommendations as to what type vary. I’ve seen people use pine and some say only use hardwood. I used alder as I had it on hand.
First: make the top and sides by cutting them out from the plywood. The important part for dimensions is that the top and bottom are exactly the same length and square and the sides are exactly the same length.
Make miter joints where these four pieces meet, but leave the sides flat as you will simply be gluing on the back and screwing on the tapa.
I cut the tips and sides to size using a circular saw then cut the 45 degree miters with the same saw. However, is you could so that in one pass, especially if you have a table saw.
I test fit all the joints, labeled those that fit best and soothed the troublesome joints with a plane.
Once everything fit, I glues them up with wood glue and clamped them using surfboard tie down straps.
Next I glued in the 1×1(cut into 10″ pieces) into the corners, coating two sides and working them into the corners until the suction makes them hard to move. Then check the joints and the square by measuring the diagonals.
Once the sides set (24 hrs typically) plane the joint faces flat making sure to taper them so the front and back pieces will lay flat.
Next, cut out the back piece of 1/4″ by tracing the existing box directly onto the plywood. As a general note, tracing is always more accurate then measuring if it is possible.
Then cut out the sound hole. You want it to be off a bit off center towards the top, but centered horizontally. You want a hole diameter of 4.25 inches as that produces a nice sounding bass thump.
Glue the back on directly and use something heavy to serve to apply pressure.
Once that dries you can trace out the Tapa from the 1/8″ plywood if you have not already. Cut that out, I like to do so oversize then plane down to flush (the same for the back).
Then mark and predrill holes every 1 15/16 inches around the edge, 1/4″ in from what will be the final edge. You also want to drill out insets so the screw will lie almost flat with the face, but be careful you don’t drill so far that the screw won’t hold the face. Also, start an inch from the sides so you don’t drill a screw into the joint and weaken it.
I used 1 1/4″ number 6 screws, but an inch would be plenty. Clamp he tapa to the fully assembled and dry box then predrill and screw in the screws all the way around.
Finish the box with a light sanding and lightly rounding all edges. Apply the finish of your choice. I’m just going to use tung oil.
Now you have a simple drum. You can mount a snare if you wish. I plan to and hope to post that process then.