Introduction: Make a Kalimba (thumb Piano)
The video link, in case it doesn't show up: https://www.youtube.com/watch?v=PMOGlNTZCS0
Hi there! Would you like to know how to make some sweet tunes? Would you like to get in touch with the origin of music? Maybe you would like to play an instrument which has a history that dates back thousands of years? Well, you're in luck, I can provide all of some of those in this instructable.
We're going to make a kalimba, which is an instrument which has existed for at least a few thousand years. However, today we're making one with a bit more updated techniques. Start by watching the video at the top and start planning for your build!
- Thin plywood
- Wooden board, or 5mm plywood.
- Hardwood, such as walnut
- Brass rod stock
- Spring steel strip, like from a metal rake or drain cleaning strip
- Screws & threaded inserts
- Miscellaneous boards, tube, mounting hardware, glue, etc
- Bandsaw (or hand saws)
- Cooking pot
- Drill, hand or drill press
- Belt and disc sander, or files and sand paper
- Masking tape & glue clamps
- Laser cutter, forstner bit or coping saw
- Milling machine
- Guitar tuner, or tuning app for smartphone
- Paint brushes
Alright, let's get going!
Step 1: Top and Bottom: Roughing
First you need to make a rigid top and bottom to your kalimba. For this purpose we chose solid wood which was cut down, jointed and planed down to a thickness of about 5mm. If you don't want to go through the trouble of making these pieces from scratch you could also use ready made plywood just cut down to size.
Decide how large you want the body of your kalimba to be and draw a circle onto the wood. When you cut it out, just roughly cut out the circle, do not cut all the way up to the line.
Step 2: Top and Bottom: Lathe
Next what we need to do is turn down a stepped shoulder on the ends of the top and the bottom. This little step will hold the side in place during the glue up later.
I'm definitely not a wood turner, so take the way I'm proceeding with a grain of salt. Make sure you mount the wood in a way that works with your lathe, and which doesn't damage the wood. I used a piece of double sided sticky tape and held pressure against the wood using the tail stock of the lathe and a piece of scrap wood in between to protect the surface.
It is though very important that you get the shoulder diameter on the top and bottom the same, otherwise the kalimba will end up with tapered sides, and will be much harder to assemble.
Step 3: Sides: Steam Bending
Now for the really exciting part! We're going to use the power of steam to make a controlled bend in a piece of thin plywood. The moisture and heat from the steam will make the plywood pliable enough to allow it to be bent and held around the cylindrical shape. Once cool and dry it will hold that shape. This is not at all dissimilar from how the bodies of guitars are made.
To start we're going to need a method of getting steam in contact with the plywood though, so we need to build a steamer! It's not as hard as it sounds, it's basically just a couple of wood pieces which fit over a pot of boiling water. They have a large hole drilled through with wire mesh fixed at the bottom. A tube is mounted to funnel the steam through (this is the steaming chamber) and a plug is fitted at the top with a couple of holes to keep most of the steam inside the tube.
Once you have the steamer built simply add water to the pot and bring it up to a boil. Once boiling just add your plywood slats and let them steam for a few minutes. Remember that steam is hot, so be careful with your fingers!
When you take the slats out wrap them around a cylindrical object with a similar diameter as the top and bottom of your kalimba. Here I used hose clamps to keep them into place, but I would probably recommend using a heavy duty masking tape instead as the hose clamps were very hard to get situated properly.
Leave the slats to cool and dry, at least over night!
Step 4: Sides: Trouble Shooting
Here is a problem you may run across. If the cylinder you're bending your slats around isn't small enough, the springback in the wood will result in the diameter of your bent slats being too big to fit the top and bottom. We could simply resteam them and wrap them around a smaller cylinder, but because they're now largely cylindrical already they won't fit back into the steamer.
However, there is more than one way to create steam. Grab a clothes iron and set the heat and steam on maximum and reintroduce some heat into the slat. Then you can rewrap it around a smaller cylinder to get it to fit the top and bottom better. It's better if the diameter of the final bent cylinder is slightly smaller than the top and bottom, than bigger.
Also, only one of the slats was resteamed, for reasons which will be apparent later.
Step 5: Sides: Trimming
Once the steam bending is done what's left is trimming down the sides to the appropriate size. This can be a bit tricky, since if you don't take off enough you won't be able to glue the kalimba together properly, and if you take off too much you will end up with a gap in your kalimba.
In this case I used a table saw to roughly remove most of the excess material, and then a disc sander to slow by slow sneak up on the final measurement. Make sure you also keep the edges of the bent slat perpendicular to each other so they meet up properly.
Step 6: Body: Gluing
Now we're finally ready to start gluing up the body.
Add a bead of glue around the shoulder you made on the bottom piece and fit the resteamed wooden slat in there. Make sure the ends meet up and hold it together with some masking tape. Put the top on, but make sure you don't glue it in, it's only there to keep things together. Finally add some weight on top to clamp and hold everything together and wait for the glue to dry.
Step 7: Body: More Gluing
Once this first set of gluing has dried we can move onto reinforcing our kalimba.
Remember the slat that we didn't resteam? It still has too big of a diameter, but right now that's perfect. This slat will be glued inside the kalimba, so the fact that it's pushing outwards will help a lot with the gluing.
Add a generous and even coverage of glue over the slat and put it down inside the kalimba. Some gluing blocks with rounded faces were made not to put any uneven pressure on any point of the kalimba, something which could result in buckling of the wood.
Make sure that the area where the ends meet on the inside and outside slats are offset from each other, so the outer gap gets closed up good.
Step 8: Finishing the Top
While the glue from the previous step dries you can consider the top, and what you want to do in terms of holes. For the body, which is a resonance chamber, to actually help to make the kalimba sound nice it needs a hole to let out the sound. Without a hole the kalimba will sound quite muffled. If all you want is a round hole you can use a forstner bit, or a small hole saw, to cut out a hole.
There's no reason why you can't go a bit more detailed though, and a scroll or coping saw could be used to make a nice figurative hole. Of course, if you have access to a laser cutter, the sky is the limit!
Step 9: Body: Even More Glue
The time has come, finally time to close up the body of your kalimba. Take the top, now with a nice hole in it, and add a bead of glue around the step, similarly what you did previously with the bottom. Put it into place and weigh it down while the glue dries.
Step 10: Body: Finishing
Alright, we're almost done with the body. The only thing we need to take care of is the bit of extra material from the top and the bottom. Easiest way to get rid of that is simply to fit a flush trim bit in a router and just route it away. A light sanding afterwards, and slight rounding of the corners for ergonomy's sake, and the body of the kalimba is pretty much done.
Step 11: Grounding Bar: Making
Now we can move on to other parts of the kalimba. Next we're making the grounding bar, which will mount onto the body and hold the tines in place and under tension. Therefore it was made from a harder wood, like walnut, so it can stand up to the extra pressure.
The grounding bar was cut out on a bandsaw and sanded into shape with a disc sander. There's nothing stopping you from doing this all manually though.
Next it was mounted into a lathe where a broad groove was milled down along the centerline to give some clearance for the tines to bend into. Two holes were drilled through the grounding bar to allow for two screws to pass through when mounting the bar to the body. Two smaller grooves were also milled on each side of the broader one to fit two metal rods on which the tines will rest.
Step 12: Grounding Bar: Mounting
We now need a way to mount the grounding bar to the kalimba. One way of doing so would for sure be to just use wood screws, but being concerned with how well they would last over time in such a thin material another solution may be better.
Start by marking the positions of the holes of the grounding bar onto the body of the kalimba. Then drill out the body for holes to fit threaded inserts, which will allow us to use mechanical screws rather than wood screws to mount the grounding bar.
Still, adding a bit of epoxy glue to the threaded inserts is not a bad idea, to make sure they're not going to move anywhere.
To make it easier to insert you can insert a screw into the threaded insert and tap directly on the screw, rather than on the threaded insert, as it may damage the wood once you get it down far enough. They need to sit flush, or slightly below, the surface of the wood.
Step 13: Grounding Bar: Rod
To hold down pressure on the tines we need one more item, a rod mounted on top of the grounding bar, using two screws which passes through the rod, the bar and down into the threaded inserts in the body of the kalimba.
The bar was made from brass rod stock which was turned down to size on a lathe. Once out it was milled down on each end and drilled with holes matching the bar and inserts, and big enough to have clearance for the mounting screws.
Step 14: Tines
Last thing we now need to make are the tines. They need to be made from springy material, as they should flex and return to their original shape when played. Many who make their own kalimbas make the tines from metal rakes, cut down to size. There's nothing wrong in that, but I wasn't about to buy an entire rake to make a few tines.
One thing which ended up working equally great was a drain cleaning strip, used for unclogging drains. The spring steel was simply cut down to shape and the ends rounded off, to provide some comfort when playing.
Step 15: Test Assembly
Now that we have all the parts we can test that they fit together properly. Just do a test fit right now, see that everything lines up and fits as it should. Don't bother tuning the kalimba right now, as you need to disassemble it again for the next step.
Step 16: Varnish
The final thing we need to do before tuning and playing is protecting our kalimba. If we left the wood untreated it would in no time start absorbing dirt and grease from our fingers, and from the environment around us. A good coat of varnish is a great barrier from this, and makes the kalimba easy to clean with just a damp cloth
I chose a polyurethane varnish for this, applying several coats and allowing the varnish to dry fully between each coat. Also, giving a light sanding between each coat with a fine grit sandpaper will dramatically improve the end result.
Step 17: Assemble
Alright, once the varnish has dried feel free to assemble your kalimba again!
Step 18: Tune
Tuning a kalimba is actually a lot easier than it sounds, but if you don't have perfect hearing and can identify notes on the fly you may need some help with the tuning. If you already have a guitar tuner that's more than enough, but you don't need to rush out to buy one just for this. There are plenty of apps for smartphones out there which can assist you in the tuning. I used a fairly intuitive one called insTuner free for the iPhone.
The process is actually pretty easy, all you need to do is move a tine in or out and pluck it, and then make adjustments until that tine is in tune. Repeat for all tines, and you're done.
Which scale to tune your kalimba to varies a bit depending on how many tines you have, and how you wish your kalimba should sound. I have eight tines, so tuning a simple octave seemed like a straight forward enough deal. There are plenty of guides online for how to tune kalimbas though, so it may be a good idea to do some googling.
Also, at this point it may be a good idea to cut down the tines to length, unless you like to have them protruding from the back of the kalimba.
Step 19: Play!
That's it though, you're done! Learn some tunes and start playing! If you want some inspiration I would suggest going to YouTube, there are many people who would love to show themselves playing their kalimbas (or mbira as its also often called). For shits and giggles look up the "array mbira" which can have hundreds of tines, and the people who are crazy enough dextrious to play them.
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Until next time!