Homemade Pipe Organ: the "Christmas Organ"





Introduction: Homemade Pipe Organ: the "Christmas Organ"

A homemade choir organ and pedalboard with a compass of one chromatic octave (C 4' to 2'). Built during Christmas break, this organ first became remotely playable on Christmas morning, 2008; it formally debuted that night when it was used to accompany Christmas carols. (And two months later, I finally succeeded in getting both audio and video on to my computer.) For details, see http://earth.prohosting.com/ssngai1/organ/organ.htm



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    9 Discussions

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    Wonderful.. Please do a complete construction layout here for us that would like to build this... I love your choice of cheap materials.. This is my kind of project..

    This is a comment for Reddnekk. I've seen valves for small model steam engines built using a small piece of copper tubing that telescopes into a larger diameter tube. The best fit for these telescoping tubes would be the tubing and a matching cap, designed to be soldered to the end of the tube...but dont solder it. Drill through the side of the cap and into the tube inside. lube the cap with heat and water (steam) resistant grease so the cap can turn freely over the tube. Now when the cap is turned so the holes align, the valve is on. Turn it so they are misaligned, the valve is off. This is similar to how rotary valves in brass instruments work.

    I haven't seen this done but a hole drilled through a copper tube containing a spring loaded and similarly drilled solid slug plunger would also work. The spring could hold the valve and pressing on the plunger would bring the plunger hole in alignment with the holes in the tubing walls and open the valve. This is how plunger valves in brass musical instruments work. They're more complex in that they typically route the input air to one of two directions but here we only want an on/off valve. I suppose the valve could be slowly opened by slowly pressing the plunger or rotating the cap as well.

    It looks like the link at earth.prohosting.com is dead - or maybe I caught it on a bad day. Either way...anyone have info?

    Hello visitors! It seems that my prohosting project page has recently hit its daily allotted bandwidth, so I am pasting the text of the webpage here. The pictures won't be available, but you can refer to the video tour of the organ in the latter half of the video above. I will try to upgrade this to a full instructable in the future. The Christmas Organ What Finally Came of the Organ Pipe Project Steven Ngai, December 2008 I had thought of constructing an organ since the summer of 2008, but because of academic factors I was able only to tinker a little here and there. To learn about some of the experimentation that led to this point, see Pipes (manufacture since revised) and Windchest/Blower. All of the final building was therefore compressed into a few days during Christmas break. The following pictures show the organ in various stages until the point when it first became remotely playable on Christmas morning, 2008. The organ formally debuted that night when it was used to accompany Christmas carols. Construction Built with an evolving plan and fervent wishes that it would work after everything came together, the whole organ is still to some extent a prototype. The earliest "permanent" part was the windchest, fed by a Fasco blower I obtained from Craigslist. Because of the current economic clime, and because the organ was just a prototype that I wanted to get working, I strove to reduce costs as much as possible. Thus the wood for the organ cost less than $20 total (!) and came from two sources: stained wood boards intended for exterior picket fencing (about $1 per 3/4"x6"x6' nominal board) and a nice particleboard I happened to have lying around. Because it would become the lid, the width of the board dictated the corresponding dimension of the windchest. Beneath each toehole is an simple pallet valve. The valve hinge, inspired by the leather used in old organ pallets, is paper. Yes, paper. In testing this proved remarkably durable even with considerable travel; fortunately, the end of the pallet travels not even 5mm in practical use. Equally shocking is that the valve returns via a rubber band that is threaded through the windchest lid. This too may seem inelegant, but the traditional spring would not only require a guide to ensure straight return but be considerably more expensive. Even though time concerns forced me to scale back my original plans to demonstrate stop action with a second rank, I never really liked the slider stop action. Inspired by, and yet much simpler than, the Austin universal windchest stop action is the dual-hinge construction demonstrated here. This allows the implementation of stops; even if the short arm is pulled down by a key or pedal, the rank may be stopped by a bar that blocks the entire row of long arms. About half of the boards I sliced lengthwise with two cuts into three pieces, forming two thicker beams and one thinner beam between them. These would become the naturals and sharps of the pedalboard. These needed to be long, measuring four of the six feet available from each board, in order to convey the pedal motion underneath the bench and to the pulldowns. Because the sharps were cut on both sides, their surface was unstained, and I got old-fashioned reversed key colors for free. The frame and front assembly were also constructed from similar pedal-width beams. The front assembly that keeps each pedal in place is somewhat self-explanatory. I would have put in similar spacers at the back end, but what I had worked well enough, and the cut boards were slightly warped on the other end. A wooden dowel passes through all the pedals near their back end, serving as the hinge; it, and therefore the pedals, are removable. The pedals return via, you guessed it, more thick rubber bands draped across the hidden backside of the assembly. You may laugh, but the feel is just about right, and I wouldn't have it any other way: there are few organs whose replacement parts you can find wrapped around your broccoli at the grocery store. (In the picture to the right, two nails for the rubber bands are visible. Also visible is the beveled edge of the natural-key pedals; think about a picket fence, and you'll understand the shape.) As part of my plan-as-you-go construction, I had the windchest on three folding chairs for several days before finally constructing a rack for the pipes and a frame for the organ. And as the pipes went in, the organ began to look a little more like an instrument. While I was unable to find a substitute for the foot construction detailed in Pipes (and those unfamiliar with this earlier experimentation will be surprised to find out what the foot is constructed from!), I did make a satisfactory advance in the construction of the upper lip by cutting directly into the pipe using a miter box-like fixture of my own construction. Here I'll digress briefly to explain the physics of the open flue pipe. When the pallet leading to a pipe is first opened, a thin sheet of air (the "windsheet") exits the flue, traversing the mouth to strike the edge of the upper lip. The portion of the wind that first enters the pipe sets up a sound wave containing a multitude of jumbled wavelengths; this propagates at the speed of sound toward the pipe's open upper end. When the wave exits the confined pipe and encounters the open atmosphere, the abrupt impedance change causes a matching wave to be reflected back down the pipe toward the mouth. As this wave bounces repeatedly between the two ends of the pipe, destructive interference causes the cancelling of all waves except those whose whole number of half-wavelengths matches the resonating length of the pipe; in this way the length of the pipe dictates the fundamental pitch and its harmonics. As the wave becomes well established, it pulls and pushes on the delicately balanced windsheet, sending the wind alternately into and out of the pipe in step with the oscillation within. This positive feedback thereby maintains the vibration that has been established. If we assume the pipe's sound contains minimal upper harmonics, the following is what happens in the steady state: as the windsheet is being blown away from the mouth of the pipe, air is also exiting the pipe through the open top, and pressure drops to a minimum at a point halfway along the pipe's length. Subsequently, in response to the partial vacuum, the cycle begins to reverse. As the windsheet is being sucked into the pipe, air is also rushing into the pipe through the top; pressure rises to a maximum at the halfway point. The rapid alternation between these two states constitutes the sound emitted by the pipe. If you look under the windchest, you will see how the pedals transmit their motion to the pallets: strings. (Actually thin yarn from Michael's, about $2 for hundreds of yards.) This was the part I had been most unsure about. Fortunately, it turned out I did not need to construct any complicated lever action: instead, I simply dropped a string from each pallet, passing it through a hole on the bottom of the windchest and terminating it in a paper clip. I then passed another string through each pedal near its back end, tying it to the paper clip in a noose. In this manner the string could be tensioned to the point that a light depression (5mm) toward the front of the pedal--about 1mm at the string attachment point--was enough to open the valve and allow the pipe to speak clearly. Because the spacing between the pipes and pedals differs, the strings formed a nice fan shape. Despite the de facto pulley action that each hole serves, the strings perform admirably. Video and audio will be forthcoming, but for now this will have to do. I am glad this project demonstrated that a perfectly functional pipe organ can be built by a hobbyist inexpensively and without specialized supplies; I hope it inspires some of you out there. Questions? Contact ssngai att gmaill dott comm.

    2 replies

    I am reading this Halloween night of 2010. I have been a calliope buff for 60 years, having been brought up in the 1930s when circus calliopes were the big thing to youngsters like me.

    I have been messing around for over thirty years, including a two month trip up the Mississippi, videotaping and recording all the steamboat calliopes, and concluding with the old Ringling Bros one at Circus World, Baraboo, Wis.

    My goal is to create a 28 to 32 note calliope which any DIYer can make himself, in his shop. For that reason I have used PVC for my pipes. But since my design is to be for either compressed air or live steam (220 degrees, 100 lbs pressure) the valves have been the biggest problem. Even solenoid valves for that many pipes will cost well over $600 in the cheapest form.

    Altho I have perused Instructables for many years, it only just tonite occurred to me to see if any of its members messed with calliopes. That is how I came to view your interesting video. I will shortly be also viewing your website.

    If you have any particular thoughts about calliopes, and have the time and inclination to express them, I would be most appreciative.


    i have an old calliope (also my cousin's name btw) in the basement and have wanted to refurbish/make it a functional piece. also i have a small toy 'piano' which is wind powered by a little blower motor. almost like a melodica but powered, i would really like to scale this up but don't know where to start. any suggestions?

    -p.s. i once almost purchased a Hohner product of similar description but seller backed out of deal. have not been able to find it online anywhere.

    This is a major accomplishment (including your other instructable). However, without a technical description, as found on your website, this is not an instructable. Why not use the classic instructable step format to explain about the physics and mechanics instead of a verbal explanation???

    1 reply

    An Instructable is the best idea - but google docs are mostly free aren't they - that would be an option also...