Originally, I thought that a multi-string version of a hurdy gurdy with individual notes may be an original idea; I have since discovered Leonardo da Vinci made drawings of a bowed keyboard instrument, and a German inventor in the 1500's built an instrument called a geigenwerk. The instrument I am building is similar in some aspects to a geigenwerk, but with the main differences being a geigenwerk has a flat soundboard,4 or 5 wheels that produce the bowing action, and a flat keyboard. The wheelharp will have a tubular body, one large wheel, and an arched keyboard.
I am progressing with my construction basically independant of geigenwerk influence, although I must offer sincerest thanks to Akio Obuchi, who has built two very nice geigenwerks, for his concept of a sliding nut pin. This detail will be brought up in the later stages of costruction.
Well, It's Feb 04, 2003... I plan to have this thing working in less than 2 months, so I'd better get busy!
inspired by local cathedral window
The wheel and pulley assembley.This is the heart of the project, and is made up of 20 seperate pieces. It measures roughley 22" in diameter x 1 1/2" thick. The frame around it is to test spin it and check for wobbles, and to see how the bearings do.So far it seems to be working pretty well. If the wheel harp does not work, I am thinking my wife can use this for a lazy suzan in the corner of the kitchen.
The upper portion of my shop where most of the construction will occur. It's small and cluttered, but at least it's warm.
The friction wheel and pulley assembly, the flywheel, and two of the nearly completed legs. I took a sheet of 1/4" plywood to a local mill over the weekend to have one of the plys sanded off. This will be used to form the thin shell of the two sound chambers. It should be ready on the 29th, then hopefully construction of the sound producing portion of the instrument can begin!
One of the finished resonators and frame ribs. There will be 4 frame ribs and 2 resonators. I have to complete the other resonator, and then I can assemble the frame components together and cover it with the outer shell.
The 2 completed resonators,the frame ribs, and the wheel before covering with the thin outer shell. Once it is covered, it can be mounted between the 2 frame rails and set up on the legs.
Finally, I have the shell (soundboard) finished. I was dreading this part, as I feared the thin wood would crack/break, or not bend smoothly. As it turns out, it was not much of a problem. I installed a temporary sound post to the resonator and scratched the surface of the shell; it seemed to be fairly sensitive to vibration. Some adjustments once it is strung will probably be in order.
Some of the parts are finally coming together-a large hitch pin ring will go over the area of light colored wood, and a tuning pin ring will go on the other end. The wheel still needs to be installed, and then bridges and strings can be put on. This color is not what I planned on; I mixed and applied some aniline dye under artificial lighting (and it looked great) but when viewed in sunlight, it appeared almost fluorescent orange. Since removing it was too difficult, I just darkened it to tone down a little. I think I like this better than color I wanted to begin with!
I now have the wheel in place, the strip on the wheel that actually comes into contact with the strings has been shaved to remove high spots, polished, and had rosin applied. I put a few temporary strings on it, and it seemed to work well. The flywheel and belt are also installed, and I am quite happy with the ratio between the flywheel and the friction wheel. The flywheel turns several revolutions for every one of the friction wheel...this will do several things. 1) maintain a more constant wheel speed 2)keep friction wheel from spinning too fast 3) provide more torque to the friction wheel to overcome drag when multiple strings are engaged at once.
Well, my April 4th deadline has came and went, and I came close to being done, but it still has a way to go. The strings are all on, but I cannot tighten them to their full tension as I do not have the steel counter-tension wires run underneath. (note the 2 tuning pins on the lower half of the tuning pin ring) My theory is, that 2 heavy steel wires will balance the stress of the 60 nylon strings all trying to pull the upper half of the two cylinders together.
Not much progress has occured this month... In addition to the steel brace wires running underneath, I added two 1/4" steel rods with threaded ends to apply more counter-tension to the rings. This worked, but the wooden rings began to distort. Although they may have settled in and went no further...I feared warpage may have continued to the point where something would break. I decided to have a 1/2" steel ring made to back up the wooden ones. I will have to unstring the wheelharp, remove the wooden rings, and cut a recessed area to inset the steel rings.
Finally! I'm starting to make some progress again....the warping problem has been fixed,
thanks to 40 lbs of steel bracing. I got the treadle
working nicely, and am concentrating on getting everything in order topside. I am surprised at the nice tremelo effect that can be obtained from bouncing your finger slightly while the string is engaged. If all goes well, I should have some short MP3 sound files posted soon!
Well, as far as the construction is concerned, it's about done, aside from maybe doing some bracing here and there. I may move the keyboard a little farther in to prevent the keys from getting knocked off.
I need to do a lot of adjustments to the tangents, or fingers that push the strings down, and some of the keys hang are hanging up, but all and all, I'm pretty happy with the outcome.