Intro: Open Source Cajon
A Cajon is a wooden box shaped drum that you can sit on and play. They are a relatively simple project with a product that works incredibly well. I want to make one as a gift for my sister for Christmas, and I made it in the best way I know how. I first designed it in CAD software and created a file that can be used with a CNC router. The design is open source so anyone who has access to a CNC router can also cut out their own. I know someone who has a big enough router to do it, and I was short on time(Christmas!) but If you don't have access to a CNC router you can also use the design to cut out the pieces by hand as they are not very complex.
Step 1: Watch the Video!
Step 2: Get the Materials and Tools
Only a few materials are needed, I used:
- 5x5' sheet of 1/2" Baltic Birch (This will do two!)
- 5x5' sheet of 1/8" Baltic Birch (you really only need ~12x19" for one Cajon)
- 1" Wooden Dowel
- Threaded Inserts
- Knob (I used this Kit that had both inserts and knob)
- 3/4" Brad Nails
- Metal Part of a Snare Drum
- Wood Glue
- Finish(I used polymerized Tung Oil)
- Sand Paper
- Screws for holding the Tapa on(The front drum piece)
- Washers for Locking Mechanism(Optional)
- CNC Router(Optional, I had access to one and used it to save time)
- Table Saw
- Brad Nailer
- Router(To round the edges)
Step 3: Cut Out the Pieces
I started with the body pieces and had them all cut out of the 1/2" Baltic birch. The front(Tapa) is cut out of the 1/8" Baltic Birch and was going to be CNC'd but it was easier to just quickly cut it with the table saw. This means I had to manually drill the holes later, which is a bit tedious since you want it to look nice.
The files are available to download above, or here: https://github.com/IdleHandsProject/opensourcecajon
Step 4: Sand All of the Edges
Get rid of any little pieces of wood and splinters so the edge goes together flush.
Step 5: Glue and Bradnail
Again, I was in a little bit of a hurry so I decided to use bradnails so I could assemble and wait less time. I only nailed the sides to the bottom and the back to the sides and bottom. The top was only glued and clamped. The front Tapa does not get glued. It is only screwed on after everything is finished.
I started by attaching the smaller inner support pieces to the sides(Picture 1 and 2). Glue and Brad Nail. Make sure the correct edge are flush with the bottom and back.
Then I attached the bottom with glue and bradnails, to the side(Picture 3).
Then the back was attached with glue and bradnails holding everything together.(Picture 4).
The inner support for the back was added(Picture 5).
Finally attach the round spacer to the Snare arm(last photo).
Step 6: Only Glue the Top
Glue and clamp the top. This will allow you to still round off the top edges with a router and not hit any brad nails.
Step 7: Cut the Dowel
Cut dowel so it sits freely in the holders on the inside.
Step 8: Build the Snare Arm
Assemble the snare arm and install the threaded insert. Place the arm over the dowel and screw in place. Temporarily install the locking knob so that it stays in place.
This is how the snare assembly works. It allows you to remove it later if you want to change it.
Step 9: Cut the Metal Snare in Half
Depending on what size you purchased, you need to cut the metal snare so it doesn't touch the top of the Cajon. For me I cut it in half so I would have another one to use in a second Cajon.
Step 10: Screw on the Snare
With the snare arm locked. Find the position of the snare where it will be fully on when the arm is in the forward position and fully off(not touching the tapa) when it is in the backward position. Screw it in place.
Step 11: Screw Pattern on Tapa
You will want to take your time here and plan out the screw pattern for the Tapa. These will hold the Tapa to the body. You can follow my pattern(in the Tapa PDF) or used your own. I'm no expert but I noticed a number of them had a similar pattern to this. Once you have the pattern, screw through one hole into the body and gently screw it in place. drill pilot holes for the screws as the Plywood can split. Once you have two screws in place it will make it easier to dril the rest of the holes without worrying about the Tapa moving.
Step 12: Counter Sink Tapa Holes
You will want to counter sink the Tapa holes so the screws are flush. This is kind of important since you will be hitting the drum, so you won't want to constantly be hitting your hands on the screws if they are sticking out.
Once this is done screw on the Tapa.
Step 13: Round the Top
Use a router and a roundover bit to round the top. This is so it is more comfortable to sit on the Cajon. This is also why we did not put brad nails in the top.
Step 14: Sand!
You can decide if you want to remove the Tapa while sanding or not. I left it on at first, then removed it. Sand until smooth.
Step 15: Apply Finish
You will want to apply the finish to the body and the Tapa separately so that they do not bond together. This was my first time using polymerized tung oil, and I'm not expert but I did a light sanding after about 12 -20 hours, and 3 coats. It turned out great.
Step 16: Play Your Tapa!
Step 17: Support These Projects!
If you think I have earned it, please consider subscribing to my YouTube Channel. I will be doing a lot more cool open source projects like this one in the future, and I would love for you to join along.
If you want to support me on the next level, and have some cash to spare. Please check out my Patreon. The more patrons I receive, the more complicated and intricate projects I can develop and share to the world. I want to make cool stuff, and make that cool stuff free and public for everyone else to make as well.