MAKE a MINI-HARP FROM a PLASTIC THROWING DISC

How to make a miniaturized harp from a plastic throwing disc or "frizbee disc". The instrument uses a disc only 10 inches in diameter and 2 inches thick including the resonator chamber. The strings are polymer elastic to make up two and one-half octaves.Sharps are made separately as will be shown.
The elastic plastic strings gives several advantages: easy tuning, good pitch stability,unbreakable, replaceable, low cost, easy to amplify, ease of portability and easy to play by anyone.
Also if anyone wishes to make professional wood construction harps and lyres see the web page
misticmodels81.com or email [e-mail] for more information.

Step 1: MATERIALS

1-Disc.Here I had available a 10 inch Pro-Flyer with a .125 to .15 in. side wall thickness. Another disc was found at a dollar store. It had a .062 wall thickness but worked satisfactorily when the 5/8 size cup-hook screw used for tuning was inserted into a predrilled 1/16 bit hole. Some plastic discs are very flexible and need to be re-enforced with a glued on resonator dish on the back for rigidity before string assembly. After the glue sets cut out a 4 inch round disc from the resonator .I like to use flower pot saucers but even a soup plate will work..
2- Tuner- Use 5/8 size nickel or brass plated cup-hook screws.Use the type with a washer collar molded on .The hook needs to be closed with a plier. This is necessary to tie the string to inside the loop thus formed.A 1/16 in. drill bit is needed for the holes used by this size screw.
3- Crimps- Strings are held in place using jewelry crimps. They can be u-shaped, tubes or bead crimps.They are available in art-craft stores and are economical.One crimp is used at the screw end and one at the anchor end under the disc.Plastic strings when knotted come unravelled so crimps must be used or glue in place . Long nose pliers are ok for crush-crimping.
4- Strings- I use stretch-cord made of space-age polymer found under Arts and Craft jewelry..Clear material can be colored using color perm-markers. The E-6000 glue will not soften the plastic 1mm. diameter strings.
4-Tools- See figure- Also a Dremel is ok for hole drilling. using 1/16 bit.
5- Cost of materials --under $5.00

Step 2: ASSEMBLY/ Layout

1-Layout- see diagram for a approximately 9 inch disc. Nothing here is very critical . Find the center of the disc. Then draw a Center-line as shown. Using a compass /dividers strick an arc. Sart the first note ,Here I used the [A] note.3.3 in. from the CL(center-line) on the top lip of the disc. Mark off .625in. spacings for the 17 Notes.. Drill 1/16 holes one-half way down from the lip at each marking.
Finally at the arc- points drill 17 holes using the 1`/16 in. bit.These are the anchor holes.They are spaced .30 inches apart.tape in a disc of paper on the inside of the disc to use for marking.
The compass-point is 2.2in. down from the center for the 3.0in. Radius arc. Drill point 'A' on the arc 2.1in. to the left of the Center point of the disc. Then mark off the .30in. spacings from 'A' pt. as shown.

Step 3: ASSEMBLY OF TUNER/STRINGS

1Tuner- after all tuner screws are squeezed closed loop start them in the predrilled holes.Use a pliers if needed to screw in.They must be screwed all the way to the collars. Then two more revolutions.The extra revolutions loosens the screw slightly for ease of future tuning.
2-Stringing- cut each string as needed about 2 inches longer than shown in the diagram.Make a crimp at one end using a crimp tube and pliers.Then tie a simple knot and pull tight. then rotate the string counter-clockwise two times around the top of the collar and pull string down into the anchor holes. Grab with a hemostat on the under side. Pull the string and pluck it to within one note less than the desired note.Lock the length on the underside with the hemo.Then place a u-crimp next to the locked hemo. Then remove hemo. Finally re-tune by rotating clockwise the tuner screw. This is then repeated for the remaining Note strings.Cut off the excess.

Step 4: ASSEMBLY/RESONATING CHAMBER

1-Resonator- Used to build up volume. Any dish can be used but must be cut out to get at the underside crimps. Here a solid pan was used. It added rigidity to the disc also when glued on.
The hole can be closed when finished stringing and crimping. I used an old CD .

Step 5: ALTERNATE CONSTRUCTIONS

THIS TYPE INSTRUMENT IS NOT LIMITED TO USE OF A DISC.
Shown here we have used various dishes, and pans, to construct a harp.
To sound like a banjo I used a small dog food aluminum can for the center resonator inside of a larger soup dish. I had to glue rods around the circumference of the dish to anchor the tuning screws.
For the screws I used .093 bits holes in the plastic rods. This type construction is wide open to the imagination and is a lot of fun to make.

Step 6: HELPFUL NOTES

1-Pitch drift stability- All types of instrument strings whether steel or nylon,etc.,drift with time when under tension.Some are very tension sensitive. Polymeric elastomeric strings also change their vibration rate [pitch] with time. The initial drift will start right after they are in tension being noted as a negative shift of the tuned note. Thus one has to expect a drift of one note to a lower pitch which stabilizes in about 2 hours. After the initial tuning after a two hour wait the strings are again re-tuned to their nominal value. The drift will be less with each subsequent re-tune. The drifting effect is only a release of molecular tension and heat and humidity has very little effect.
When multi-strand elastomeric string is used the long term drift is very small. Drift of 1/2 note maximum is noted over a 2 month period. Problem is -suppliers are hard to find thus this is why I use solid mono-layer type string instead and need to re-tune more often.

2-Tuning screws- The only ones as described above I use is brass plated or nickel plated steel.The reason is the collar. it must be integral with the hook .It is needed to contain the string from pinching
as the screw is rotated clockwise[i.e. tuned}. Cost of 100 screws is under $4.00 in most hardware stores.
3-Tune-up - I have used my $20.00 Casio[R] . Also I can use my Chromatic harmonica . Pianos are nice too if you can lug it to your work bench.Or, you can make one of my Instructable mini- tuners,tune it at the piano and use it. Obviously my electronic tuner [$19.00] can be used but I find it cumbersome but accurate.
4-Amplification- I use a wireless mike I bought at a drugstore{Hanna Montana no less}.Works fine.
You may cut a 1in,Dia. side hole in the resonator to insert the mike tube.Tune your FM set to the noted frequency on the instruction sheet.Play as loud as you want.
5-Tuning range- I use about 2 octaves starting at Middle C of the Piano. Lower frequencies [Notes} can be constructed to Cm-1. but more room is needed or use a 12 inch disc.
6-Sharps[flats] notes are generated by applying slight finger pressure just down from the tuner screw about 1/4 inch and pluck the string.Some note bending will be noted but a 1/2 note increase is easily obtained. C note can be increase to C sharp [C#]. Extra strings for sharp notes is too involved and unlike a harp there is very little room for more strings. Bflat is actually A# .
7-Marking- notes location can be actual letters, pen markings, or as shown drawing a treble and base clef drawing. I also red ink mark my Cm string. Any color is well taken using a permanent felt tip marker. Green ink can be a G-string, etc.

I am going to submit this Istructable for the Music contest. So let me know if you can make this item.

Step 7: SOUND VIDEO