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Thumb Piano 

Make] Projects 

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build, hack, tweak, share, discover,- 

Thumb Piano 

Written By: RP Collier 


Drill bit (1) 
upto 1 / 4 " 

Hacksaw (1) 

to trim tines and, if desired, the shim. A 
hammer can be used instead of a saw to 
trim spring steel tines — clamp the tine 
in a vise and strike to bend it until it 
breaks. Wear eye protection! 

Hand drill (1) 

Screwdrivers (1) 
flat blade or Robertson bit for the 
grounding bar, and whatever type is 
needed for your chosen fasteners 
(including hex key) 


Grounding bar (1) 

from the electrical section of a hardware 


• Piano body (1) 

Examples here include a salad bowl, 
cigar box lid, wooden box, and aluminum 
block. You can use almost anything 
that's easy to hold and strong enough to 
withstand the fastening of a grounding 
bar and possibly a shim. Hollow or thin 
materials are good sound resonators: if 
your chosen body material doesn't 
resonate well, attach a resonator. 

Shim (1) 

can be a chunk of wood, metal, or 

plastic. 3/8" thick or thicker 

Fasteners (1) 

such as hex screws, machine screws, 

wood screws, or nails 

Tines (1) 

from a material firm enough to vibrate 

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Thumb Piano 

when plucked up to 1 A" wide: hairpins, 
wire, bicycle spokes, umbrella ribs, 
teriyaki skewers, knitting needles, street 
sweeper bristles, etc. 

Grounding bar (1) 

from the electrical section of a hardware 


Salad bowl (1) 

Square dowel (1) 

Spring steel (1) 

from your local industrial steel 
distributor, trimmed to various lengths 
from 2" minimum to 6" maximum 

Wood screws (3) 


The thumb piano, known as a kalimba, mbira, and by many other names, is a lamellaphone 
that uses prongs called tongues, keys, or tines that you pluck to generate acoustic 
vibrations. The length of the tine determines the pitch. 

Generally, the thumb piano uses some kind of mechanism as an anchor that puts a great 
deal of pressure over the tines and across 2 bridges, leaving the free lengths of the tines 
room to vibrate. The tines are usually of the same material and gauge (thickness) to ensure 
that 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 while at the same time permitting the tines to 
be swapped out and tuned with ease. 

I've included 2 materials lists: a generic list and one that is specific to the salad bowl 
kalimba shown here. Experiment, explore, and find configurations that work for you. 

The tines in the video are made of (from left to right): blue tempered spring steel, hairpin, 
street sweeper bristle, unknown steel lattice debris, electrician's snake, knitting needle, 

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Thumb Piano 

street sweeper bristle, bicycle spoke, spring steel, umbrella rib, plastic hobby/craft brush, 
and plain steel wire with the end splayed by hammering. 

The length of a tine determines its pitch. To tune a tine, loosen its screw, scoot it forward or 
backward a bit, retighten, and plunk. 

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Thumb Piano 

Step 1 — Fasten the grounding bar. 

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Thumb Piano 

• The grounding bar is used by 
electricians to ground house circuit 
wires. It comes in various lengths 
and can be found in most local 
hardware stores or 
builder/contractor supply centers. 
The empty slots (2, 3, or more) 
come drilled all the way through — 
this is where fasteners can be used 
to attach the bar to something. But 
you may need to drill through if 
your slots aren't in the perfect 

• To anchor the grounding bar, 
simply make 3 holes with a hand 
drill into the surface you've chosen 
to be the body of the instrument. 
The screws shown in the bottom 
photo are hex head 10-32 machine 
screws (smaller and different types 
of machine screws could be used) 
secured with T-nuts, speed nuts, or 
standard nuts with lock washers 
and fender washers. If screwing 
into metal, you can use a tap to 
thread the holes. 

• If you're going to mount the bar on 
wood or thin metal such as a tin 
can, you may need only 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, and add a bit of glue to the 
holes before driving them firmly. 

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Thumb Piano 

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 2 — Add shims, if necessary. 

• The tines need room to vibrate, so depending on the type of surface chosen and the way 
the bar is mounted, you may need to lift the grounding bar up off the instrument body using 
a shim. This just requires 3 more holes using the grounding bar as a template. 

• The top photo shows shims made of 3/8" steel bar and wood square dowels. Plastic, clay, 
Bondo, Rock Hard Water Putty, or other materials could be used. The shims pictured are 
trimmed and clean, but they could be made of scraps, rough and with irregular edges, as 
long as the thickness is consistent. 

• The grounding bar provides a way to hold the tines using easily adjustable setscrews. The 
bottom 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. 

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Thumb Piano 

Step 3 — Add the tines. 

• The tine can be anything that will 
vibrate and that will 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. 

• Metal tines can be bent away from 
the instrument to give more 
vibration room, which makes it 
easier to play. 

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Thumb Piano 

Step 4 — Final thoughts. 


• If you use a body that has a lip or an edge, like a wooden box or desk drawer, the tines are 
free to vibrate over the hollow of the receptacle, so a shim isn't necessary. 

• The inside of a cigar box lid can provide a shallow receptacle that fits well in the hands. 
Again, no shim is necessary. The tines shown at right are bamboo teriyaki skewers. 

• In the photo 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 %"-thick block, and there is an aluminum shim. 

• I wanted to make something sleek that looks machined, but in actuality I 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. 

This project first appeared in CRAFT Volume 06 , page 38. 

This document was last generated on 201 2-1 1 -03 04:24:30 AM. 

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