This is a method to quickly and easily make a musical instrument capable of melodic percussion and noise experimentation.
The thumb piano, known as a kalimba or mbira and by many other names, is a lamellaphone that uses plucked prongs called tongues, keys or tines to generate acoustic vibrations. The length of the tine determines the pitch.
Generally, the thumb piano uses some kind of mechanism to create a great deal of pressure to anchor the tines across 2 bridges which allows the free lengths of the tines room to vibrate. The tines are usually of the same material and gauge (thickness) to ensure consistency so the pressure is distributed equally holding everything in place and in tune.
The method shown here is simplified and wonderfully versatile. It allows the use of more fragile, delicate, and unusual materials for the body of the instrument, and it provides a way to use oddly shaped tines of different materials at the same time while permitting the tines to be swapped out and tuned with ease.
There are interesting possibilities here: a simple armature or jig that becomes a tool with which to investigate the sound that different materials make - how they vibrate, how they resonate and how different combinations of factors can change the sound quality.
Experiment and explore and find configurations that work for you.
Video link in Step 6.
Step 1: The Grounding Bar
The grounding bar is an item used by electricians to ground house circuit wires. It comes in a variety of lengths and can be found in the electrical section of most local hardware stores or builder/contractor supply centers.
The bar shown is about 4 1/2 inches long and 1/2 inch in width.
The 3 empty slots are drilled all the way through, this is where fasteners can be used to attach the bar to something.
Step 2: Fasten the Grounding Bar to a Surface
All you need to do is make 3 holes with a hand drill into the surface you want to become the body of the instrument.
The screws shown in the photo are hex head 10-32 machine screws. They are used in the thumb piano shown in Step 9 by using a tap to thread the holes. Otherwise, these need washers and nuts to tighten for anchoring the grounding bar, or instead of washers, some kind of plate for the nut to press against. Smaller and different types of machine screws could be used adding washers and maybe lock washers as needed.
If you are going to mount the bar on wood or thin metal like a tin can, then you may only need a hammer and nail to make the 3 holes.
With wood, just use wood screws or something similar. Nails alone might possibly do the job with a bit of wood glue - start the holes with a nail, add a bit of glue to the holes before driving them firmly.
Heavy duty epoxy, riveting, welding or even slotting a surface with a milling machine or router are some other ways to anchor the bar.
Step 3: Shims Might Be Necessary
The tines need room to vibrate, so depending on the type of surface chosen and the way the bar is mounted, it may be necessary to lift the grounding bar up off the instrument body using a shim. This just requires 3 more holes using the grounding bar as template.
The photo shows a steel bar and a wood square dowel for shims. Plastic, clay, bondo, rock hard water putty or other materials could be used.
The shims in the photo are trimmed and clean but they could be made of scraps, rough and irregular of edge, as long as the thickness is consistent.
Metal tines can be bent away from the instrument to give more vibration room (action), the more action the easier it will be to play.
Later steps show examples where no shims are needed.
Step 4: The Grounding Bar Open on a Shim
The grounding bar provides a set screw method to hold tines.
The photo shows the bar on a shim with the screw slots opened.
You need a regular flat blade standard tip screwdriver or a driver with a Robertson bit.
Step 5: Adding a Tine
Inserting a tine.
The tine can be anything that will vibrate and can fit the hole.
This photo shows a blue tempered spring steel tine.
Crank the screw down tight to anchor the tine.
This grounding bar can hold 12 tines.
Step 6: Body and Tine
This demonstrates what is great about this method - you can use tines with a variety of shapes, sizes and materials at the same time.
Tines shown in the photo below the video from left to right:
blue tempered spring steel
street sweeper bristle
unknown steel lattice debris
street sweeper bristle
plastic hobby/craft brush
plain steel wire - the end splayed by hammering
There is a video of this thumb piano being played.
Very roughly tuned and I used a guitar tuner pickup to run signal into a delay and guitar amp. Normally I would put the pickup closer to the bar but I was using a rubber band to hold it in place so where I placed it suited the size of the rubber band. The audio is just what the little point & shoot camera microphone was able to catch.
Step 7: No Shim Needed
By using something for the body with a lip or edge, like a wood box or desk drawer, the tines are free to vibrate over the receptacle so a shim is not necessary.
Step 8: Cigar Box Lid
The inside of a cigar box lid can provide a shallow receptacle that fits well in the hands. Again, no shim necessary.
The tines shown in the photo are bamboo teriyaki skewers.
Step 9: Other Emphases
This is an example of the grounding bar used on unusual materials but in a conventional way.
The tines are spring steel and uniform across the span.
The body is aluminum, a 3/4 inch thick block, and there is an aluminum shim.
I wanted to make something sleek that looks machined but I really just used a cheap, much abused drill press. I used a tap to thread the anchor screw holes, putting the tap in the drill press and turning the chuck by hand.
Surprisingly, the thing is so heavy that a hollow door on sawhorses makes a good resonator for the instrument.
Step 10: TRY THINGS
The photo near the bottom of the page shows a zither from a thrift store mounted with the grounding bar kalimba which holds uniform spring steel tines. The bar is sitting on a steel shim and the tines are slightly bent to get above the zither strings.
Example of instrument using plastic swizzle sticks for tines
New 2008 all thumb piano audio album:
Lamellaphone - http://cdbaby.com/cd/rpcollier4
For more of my thumb piano experiments:
thumb pianos by RP Collier
thumb piano demos:
faux fur demo
chopping block lamellaphone
more mostly thumb piano videos:
videos by RP Collier
Example for tapping, scraping and bowing:
Greg Bossert of Suddensound.com also provides a great example of using mallets or drumsticks to tap long tines in the grounding bar which results in good bass tones:
Check out the sound sample: