BUILDING A WURLITZER 105
Part Two by Howard Wyman
In last months article I spoke briefly about the pallet valves in the windchest. These are the valves which open to allow the air to flow to a certain pipe or pipes. The lower part of the windchest receives the pressurized air from the bellows. The upper part of the windchest is divided into 41 channels, one for each note. In between there is a pallet valve for each channel. When a valve is opened by the player mechanism it allows the air from the lower part of the chest to flow into that particular channel and to the pipe or pipes that are connected to that channel. Each pallet valve must make an airtight seal when it is closed and that is accomplished by facing each valve with a suede surfaced leather backed with felt. The most efficient way of doing this is to cut a strip of felt whose width is equal to the length of the wooden pallet valve and whose length is slightly greater than the sum of the widths of all of the valves. Then cut a piece of leather the same length but about 3/4 inch wider. Glue the two together with one of the long edges aligned. Then, with the felt side up, glue the wooden valves side by side onto the felt. After the glue has set, you can run a single edge razor blade between the valves and cut them apart. The extra leather tail at the end of each valve serves as the hinge. PHOTO A shows the leather hinges glued in place. In this photograph you can also see the springs that hold the valves in the closed position as well as the guide pins which keep the valves from moving sideways. The springs are made of piano wire.
The Wurlitzer 105 Band Organ plays the Wurlitzer Style 125 roll which will play 41 notes plus snare drum and bass drum. The 41 notes include 14 melody, 13 counter melody, 9 accompaniment, and 5 bass. One note may sound several pipes and so the organ has 97 pipes. For example, in the melody section there are four ranks of pipes, melody flutes, violins, piccolos, and flagolets. To illustrate, let us say we open the valve for the melody note of C. Four pipes will sound simultaneously, all tuned to C but each with a different timbre or sound quality. In the accompaniment section each note will play two pipes, a flute pipe and a cello pipe. In the bass each note plays two pipes, a bourdon and a cello pipe. The counter melody has only one pipe per note, a trumpet pipe.
PHOTO B shows the windchest in the upright position. In this photograph one can see the openings for the pipe feet. Also it may be seen that some of the pipes fit on risers above the chest. Each pipe foot is tapered and fits into a tapered hole. This provides an airtight fit. I used a small lathe to make the tapered feet, but I was not certain how to go about making the tapered holes. Here is the solution I finally came up with. On the lathe I turned a tapered piece similar to a pipe foot but with a sort of shaft at the large end which I could lock into the chuck on the drill press. I then cut a piece of sandpaper which I glued around the taper. The most difficult part was figuring out the curved shape which would wrap around the taper. Then I drilled each of the holes for a pipe foot with a straight drill but made it slightly undersized. Then I used the taper with the sandpaper to shape it to the correct size. I am certain others can think of a better method, but it worked for me.
Next month we will get into the building of some of the pipes.
Editors note: Howard is a retired electrical engineer and lives in Florida. Most of his career was at the Army Night Vision and Electro-Optics Laboratory. He became involved in mechanical music with the purchase of a non-working player piano. As you will see in his articles, Howard is a highly skilled craftsman. Building your own band organ is a real accomplishment and Howard does beautiful work. Howard can be contacted at: email@example.com