DIY / Homemade Danmoi Inspired Metal Jew Harp - Material

The Jew Harps I built are based on a dan moi design. Those homemade versions are not as good as the dan moi ones, the “sound” is not long lasting, and the harp is not as stiff as a brass one (replacing the tongue in its optimal position can take a bit of your time). However, I wanted to find a way to make metal dan moi inspired by the “french” credit card dan moi.
Just a mention on the contents of this instructable-->attribution non commercial sharealike. You can re-use my texts and my pictures, modify or whatever, if you do so please cite the author, my work or even better put a link to this instructable. I would appreciate your cooperation :) In addition if you have any comment or improvement that you would like to share with me please do it. Last but not least, Share with me the metal homemade danmoi you made. I will probably add a gallery for your danmoi later on.

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important notice/ safety issue


This music instrument is called a lamellate jew harp as explained by Robert Vandre www(dot)rvandre(dot)de/‎ (as opposition to the bow shaped jew harp).
Figure 1: The lamellate jew harp is structured in several subcomponents:
the tail or pluck where the energy input is given (by hitting/plucking it), the intermediary frame part, which acts as a spring,
the tongue or reed responsible of the sound formation by entering the wished vibration motion,
the frame which is rigid (and must act as the energy storage but this is a guess only),
and the frame´s end or hold location.
The player must place his/her lips on the frame - rigid part so that the end of the tongue can vibrate freely “in” the mouth of the player. See the appendix playing modus operandi in the last part of this tutorial.

A summary without extensive comment (I recommend however to read the rest as useful information and experience I made are shared thereafter)

you need:

• to be careful/preferably not alone in the room in case of injury

• to be patient because you would have to make several attempts (Per dan moi 15 min to 60 min)
• to have a soft steel sheet cut from a candy box
• the following tools see the second picture:
  • a cutter
  • kevlar or similar protective gloves
  • screwdriver for electrotechnic
  • a permanent marker
  • scissors
  • piece of wood (a line is carved on one side using the scissors)

A) cut a wedge form out of the soft metal sheet 1 cm one side to 2.5 cm the other side (scissors)- see the third figure

B) mark a wedge reed on the backside (not the coloured side), put the metal sheet on the piece of wood (straight side) and start attacking the metal sheet following the wedge mark as shown in the fourth picture
with the aid of

• The cutter (and a ruler to keep it straight) in one direction and the other
• and after, you did that repeat this operation with the screwdriver
• repeat several times both

C) On the coated side you see clearly the wedge shape boucing out of the metal sheet.

Repeat B) but this time put the metal sheet on the piece of wood (carved side). Try to make the carved line below the cut lines.

D) you finally obtain to cut through the metal at some points? Yes? Good! then Complete the cut along the wedge mark

E) the reed is apparent and complete? Good! it is time to smooth the edges of the metal sheets and of the reed part with a file/ sand stone. Keep the reed straight with the help of the straigh claw. (a small space must be obtained)

F) The reed is OK and look like the fifth picture? Edges and sharp needles are not anymore a danger? Then go for the final step.

G) final step:

• mark the jew harp with the pen to define the shape
• bend the sides of the "jew harp" as shown on the figure 1, along the frame (120° will be optimal), up to a few millimeter before the reed starts. alike the sixth picture
• Cut the tail with scissors according to the marks
• Smoothen this part with a file/sandstone
• check that no more needles/splinters are found and smooth those if it is the case!

H) Tadaaa! you obtain something close to the first picture? OK! Enjoy it!

Take a metal box made of soft steel (use a magnet, if it sticks to it then that s perfect, it is not aluminium) see figure 2 – usually small candy and cookies metal boxes do the job as well. The
important is to choose the material wisely, thus no aluminium preferably, it makes a poor jew harp material from my experience. (it is tough material which will not allow plastic deformation without breaking... you do not want the effort to be ruined caused by choosing the wrong material) A clear drawback of the soft steel here is that all metal sheets are not equal... So you will always need a first attempt to learn how the material will answer.

you need:

• an adult in the same room if you are not 18 old, and to be very cautious because you can injure yourself easily during this procedure (needle like metal splinters can penetrate your skin easily... so be careful, and clean your working place as often as you can)

• as illustrated in Figure 3: a marker, a cutter, kevlar gloves for your protection (this very sharp blades need to be handled with extreme caution-severe damages can result.... you do not want to be transported to the hospital with a finger part missing right?), a screwdriver (for electrotechnician, those are sharp and hard enough), a flat claw, scissors and a piece of wood. As you can see in figure 4, the wood (here a spatula for the famous french/swiss molten cheese speciality-the "raclette") has been carved out using the scissors following a straight line.

Use the scissors to cut a metal sheet out of the box (figure 5). As the edges are usually doubled, cutting through can be difficult. Use the cutter carefully to cut through the edges. The scissors are easier for cutting through the metal sheet then. Be careful, straight and clean cuts are not so easy to obtain. So it may results small spikes/needles like metal parts. As it may hurt and, please sand the edges before going further. Again use protecting gloves. Here we obtain a flat metal sheet (figure 6).

Cut a wedge shaped small piece from the metal sheet. About at least 12 cm long and 1.2 to 2.5 cm large as shown in figure 7.
Mark the back of the metal piece with a permanent pen in a trapezoidal wedge shape (4 cm long and a 4 mm at the basis) as illustrated in figure 8. This would become the reed, the vibration tongue. The material "nature" dictated the length and width of the reed. You need to find compromise maybe you will need to make 3 or more of the same metal sheets in order to get a satisfying result. The wedge form is important. Other form cannot work. Believe me I tried. I read a lot of music theory to increase weight at the end of the tongue to decrease the frequency of vibration... but this strategy only leads to unfruitful shapes that are not allowed to vibrate. So from a rectangular shape to a wedge (basis of the tongue the larger part, and the end is the summit of the wedge), all the combination with straight lines may work. See the appendix

First of all, "attack" the metal sheet as
shown in figure 9 using the cutter blades following the drawing (using the uncarved wood piece, straight side as support). Then carved the metal using the screwdriver. Repeat the procedure following one cutting direction and then the other until you can see as shown in figure 10 a clear metal bouncing on the front of the metal sheet (alternate cutter and screwdriver).

-at this point used the carved wood as a guide and do the same. The carved wood guide is an empty space below the sheet of metal which will allow locally a further deformation of the metal sheet. At some point, the metal become thinner and thinner.

After several repeated carving and cutting, you will be able to cut through the metal sheet (see figure 11). The carved wood support will guide you and help you to cut on metal sheet without important and irregular deformation. This is important for getting a rather clean and uniform shape.

Figure 12, Maintain the reed with the flat claw, take the thin file and then start sanding the reed side to obtain a regular and straight edge (try to sand the sharp edges of the frame sides as well to get a uniform space between the reed and the fringes)
the free space is thus enlarged, but be careful to not remove too much material. Half a millimetre is already too much (we need the reed vibration to impose repeated air motion as well otherwise no sound can be produced). Oppositely, removing only slightly some microns of the edges will not be that beneficial. Hence, the tongue would frequently hit the edges of the frame. Which in turns cause sound damping or even cancelling.

On figure 13, you can see the light between the tongue and the edges of the frame.
As you can observe that with the razor blade, some lines are drawn on the metal sheet. The metal sheets will be bend along those lines with the aid of the flat claw. This procedure helps to obtain straight metal 3D structures . The shape of the jew harp is obtained by scissoring the metal sheet (draw a mark on the metal sheet as depicted on figure 14) and by bending along the frame part. Be careful, this bending operation will increase the rigidity of the frame drastically, and can affect the tongue as well. So try to restrain yourself for the rigid part of frame to the 1 to 5 mm before the tongue/reed begin. You can sand or file the metal surface one 10 to 20 mm from there onto the tail. Please bend the metal over 90°, and preferably at least at 120°, this construction enables playing with a certain comfort... you will not cut your lips with sharp edges. Although you need to impose an important curvature to the metal sheet, avoid contact between the edges of the metal sheet and the metal frame or that the metal sheet will be in the course of the vibrating reed (this would restrain further the vibration modes of the frame part and as the same time will damp the vibration, you do not want that). However, you can make a stronger curve with contact at the very end of the frame part. This will allow a more pleasant grip. The frame needs to be stronger and stiffer that the tail and the tail must be more springy than the rest.

Finally you will obtain a jew harp that is similarly shaped as the one depicted below (figure 15). Another example is given in the next part. Important: Check that you have nothing sharp (edge, needles) that can injure you-if you have some--> sand this off! . You can start playing!!! Enjoy!

Appendix – Forming a flat spring shape:
Obviously, on figure 16 the sides of the tail were not cut away in a dart like shape. Yes.
This jew harp was designed for experimenting improvements of the vibration duration.
This process was long and frustrating.
The jew harps made from this box were not vibrating really nicely in comparison with smaller candy metal box I worked with before.
Recently, I found out some tricks to improve the response of the system and the restitution of the input energy (by hitting the tail). One of them is to form a real spring on the tail part (on the picture you can notice some curves obtained by bending the metal with the flat claw along the tail part, you can see also that the metal surface has been sand off to remove the coating there). Try to remember, the paper jumping frog origami construction in order to get similar effect.

Another trick consists in a modified playing protocol see modus operandi.

Appendix - tongue shape:

Figure 17: the two first shapes cannot be employed, the tongue will hit the walls of the frame during vibration.
This is only forbidden by the geometry of the tongue. As the tongue become “shorter” during vibration (the tongue vibrates in a ?hyperbolic? form/modus), the end which is greater than the base will encounter in its course a narrower path than its geometry allows. This path results in a motion stop.
Actually I said it is not working...It can work when you hit very softly / gently the tail. As a consequence it will not be loud and will be a very quick one... So... Dan moi are wedge shaped... that s for the same reason than mine...
All the others, parallele and wedge forms (3,4 and 5) will be not restrained in their motion.

Appendix – Modus Operandi
You can play the jew harp like a dan moi by holding the jew harp at the frame end firmly (see figure 1), posing your lips on the frame, and hitting the tail with the fingers of your other hand. In addition you can use your teeth against the rigid frame part. Or you can play the modified protocol. Two playing modus are possible (maybe more on the same models).

Figure18: Once you put the jew harp between your lips, your hand that held the frame end is removed and placed at the intersection between the frame and the tail. The finger and the thumb pinch sidely the metal sheet. Start playing :) With a bit of experience, you will obtain a longer vibration duration (or at least a better resonance).

Figure 19:The second consists in placing your thumb and a finger such as you create a tension between the frame and the tail. (one finger of the frame end and the other is placed around the intermediary region between the frame and the tail, roughly 1 cm from the tongue's begin) Then plucking the tail with your fingers. Appendix - sound emitted Here you can load the end of the tongue with wax or by welding some metal on it. As a result the frequency will drop. Oppositely you can smooth the tongue (with more effort given at the end), thus the frequency must increase.different sources may help you like the work of Bart Hopkin or if you look for instrument making and music theory and physics