(Photograph courtesy of Bob Gilson.)

Cast iron tune indicator wheel in National piano #348. The tune indicator wheel mechanism is always located in the same area, the upper left quadrant of the piano case. Behind it hangs an electric lamp that serves to back-light the tune numbers, but also to shine light throughout the entire upper part of the piano case. In most National pianos this lighting insures that the piano action stands out through the front glass window, adding to the allure of the automatically played piano. However, this particular piano has been factory retrofitted with a dog race diorama, blocking off any view of the piano action, but instead adding an attractive and colorful sylvan background painting as the setting for a dog race trade stimulator.

In this photograph the player system is switched off, and so the tune indicator wheel's metal blocking shield is lowered, hiding the number position of the wheel. With the upper front panel in place the circular aperture through which a tune number would show (when the instrument is playing) is blanked out by the shield. Immediately below the tune indicator wheel is the front chain sprocket for an intermediary countershaft that is located between the stack and the tune indicator wheel mechanism. This mini-countershaft basically moves the chain-fall from the backside of the tune indicator wheel forward, toward a chain-fall cutout at the front of the Simplex stack. From here the chain falls straight down through another cutout in the "keybed" shelf, and then on to the lower countershaft that is connected to and synchronizes the tune indicator wheel with the angular position of the revolver magazine.

(Photograph courtesy of Bob Gilson.)

Front side detail of cast iron tune indicator wheel in National piano #348. This closer look at the iron casting reveals the graceful delicacy of the pattern maker's workmanship. The small pneumatic that raises the blocking shield is connected directly to the stack vacuum supply, so that whenever a music roll has been selected, and the player system is in Play mode, the selected tune number will be made visible.

(Photograph courtesy of Bob Gilson.)

Back side of cast iron tune indicator wheel in National piano #348. Most predominate in this photograph is the top side of the pneumatic that raises the blocking shield. Notice that there is an adjustment screw on the pneumatic's movable leaf, which is used to limit how far the pneumatic can collapse when a vacuum is applied. It is also interesting to note that the chain sprocket that rotates the tune indicator wheel is mounted on a shaft extension. This short extension is made necessary only to accommodate the mounting and bearing spacing constraints imposed on the intermediate countershaft located immediately below the tune indicator wheel. The sole purpose of this intermediary shaft is to move the chain-fall from the back of the tune indicator wheel forward, toward a cutout hole near the front edge of the Simplex stack.

(Photograph courtesy of Dana Johnson.)

Cast iron tune indicator wheel in National piano #7524. This view shows a cast iron tune indicator wheel assembly in an instrument with a National built stack. Here there is no shaft extension on the back side of the tune wheel indicator. The chain-fall is diverted to the left side of the stack by a pair of idler sprockets, whereupon it then falls downward through a cutout in the "keybed" area shelf, and then onward to a countershaft that is connected to the revolver magazine's main shaft. The routing of the chain as shown here seems to be normal path for pianos with a National built stack.

(Photograph courtesy of Dana Johnson.)

Fabricated steel framework tune indicator wheel in a National coin piano. This is a typical tune indicator wheel installation for a piano with a National built stack. The chain from the drive sprocket on the backside of the indicator wheel is diverted to the left by a pair of sprocket idlers, with the chain thereafter falling straight down and through a cutout in the "keybed" area shelf. The fabricated steel framework is probably less expensive to build than is a cast iron unit, and less subject to impact breakage if handled roughly.

(Photograph courtesy of Dick Hack.)

Front view of fabricated steel framework tune indicator wheel from a National coin piano. This tune indicator wheel assembly is from a parts box, made up of loose items from a junked out National piano with a Simplex stack (piano serial number unknown).

(Photograph courtesy of Dick Hack.)

Rear view of fabricated steel framework tune indicator wheel from a National coin piano. This rear view (of the loose parts box specimen) shows the ragged and yellowed paper on which the tune numbers are printed. It also clearly shows the drive sprocket on the backside of the indicator wheel, and the operating layout of the pneumatic and blocking shield that hides the tune numbers when the player system is not active and in Play mode. Notice that this pneumatic has an adjustment screw in its movable leaf, limiting the travel as the pneumatic collapses when a vacuum is applied.