Crank Organ

While searching the web for an organ with a keyboard to build, I found the plans to this 20 Note Crank Organ designed by Walter Hoffle of Germany. Mr. Hoffle decided to retire from his organ business and relinquished rights of the crank organ plans to Wiel Geraats. Mr. Geraats translated the plans to both Dutch and English languages.

I ordered the plans after considering that by turning a crank, anyone without the knowledge of music can play this organ. But, I did not know the challenge of building a crank organ until the plans were received. Thinking, “Here you are with a good set of plans and instructions without ever seeing or hearing a crank organ.” But with Mr.Geraats answering my questions with email and by studying the beautifully drawn plans and well written instructions I have finished the organ in less than six months. The finished organ is shown in the photo above.

This photo shows the front and left side of the case. I used regular pine plywood but wish I had used Baltic birch. It is much better plywood and the cost is not much more. Where I live birch plywood is available but a hassle to purchase and pick-up.

The photo on the right illustrates the back of the case with rear access to the bellows. This is the only way in to install the reservoir bellow spring.

The command box is shown in the next photo. A small metal lathe helped complete all the machine work required to fabricate the crankshaft, bearings, command block, the drive and driven wheels, and all the other machine parts required to make the organ work. Also a cross sliding vise mounted on my drill press was indispensable for completing many of the bearings and other parts.

In the picture to the right you can see the valve chest and to the right of that is the upper board where the pipes will be mounted. Underneath all that are the bellows.

I recently finished the Transport Car to have it ready to load the organ when it is finished. I like the design of the car; it was easy to build, and the 16" bicycle wheels with whitewall tires are all in harmony.

The bellows are shown with the photo on the right. Note the spill valve on top of the reservoir. It's purpose is to maintain a constant air pressure of 150mm water column. Below the reservoir bellow are two double action bellows to supply air to the reservoir and then to the organs music pipes. This will illustrate how it all works. I love it.

On the left are a few of the 56 pipes needed to complete the Hoffle Organ. They all are made of cherry wood and finished with a couple coats of lacquer and then polished.

The pipes required many hours of meticulous work and time to complete all 56 pipes. In the end all the careful work paid off when it came time to fine tune the pipes.

This concludes all the photos taken during construction of this fabulous organ. I wish I had taken more pictures but it is difficult to stop doing something you are enjoying and shoot photos.

The Busker Organ

Pictured here is my completed John Smith Busker Organ made from Mr. Smiths plans. With the plans he includes a DVD and a paper test roll. Every question I had was answered in this complete bundle.

The easy to build pipes were constructed of balsa and to the front of each pipe a thin veneer of figured sycamore was glued. The front hardwood covers are made of purpleheart.

The organ sound heard here is from this interesting light weight organ.

Close-up view.

I have attached a neck strap and found the organ must be pushed out and to the right of the body while cranking.

To make cranking the Busker more convenient I decided to move the cranking handle to the side using two 90˚ nylon gears. The two photos illustrate how to relocate the crank handle.

The two gears were purchased from McMaster-Carr in Atlanta, Georgia, USA for $3.17 each. They are number 7297K16, molded nylon 20˚ pressure angle miter gears, 24 pitch, 30 teeth, 1.25” pitch diameter, with ¼” bore.

First I removed the ¼”crankshaft from the organ and shorten the rear of the shaft to be flush with the rear bearing or plate. Then attached the driven gear to the shaft with a 3/32” roll pin and reinstall the crankshaft.

After holding the drive gear in place, measure for the location of the drive gear flanged bearing. The flanged bearing was made by drilling a ¼” hole through a 3/8” round piece of steel bolt cut to 1-5/8” long with a steel washer brazed to the end forming a flange. Since the RPM of the crankshaft is minimal, steel should make a good bearing after oiling. Brass or aluminum could be applied here.

Threes screw holes are drilled in the flange for mounting through the side of the organ with an extra piece of wood glued inside to help hold the flange tightly in place. With trial and error the bearing length is determined by rotating the drive gear back and forth until the gears turn smoothly. After determining the position of the drive gear, drill the gear and shaft to install the rollpin.

The hand crank could have been installed in the middle of the side but the driven gear would need to be placed between the two crank throws during construction of the crank shaft. Metal gears could be purchased and used in place of nylon for $18.17 each.

Cranking it is much more convenient with its new location.