(Photograph courtesy of Bob Gilson.)

Hammer rail control in National automatic piano #348. The lower pneumatic lifts the hammer rail (hammer rail up—tracker bar hole #3) by means of a wire connected to its bottom movable leaf. Once the pneumatic is fully collapsed the felted wooden hook latches over a metal blade, which thereafter keeps the hammer rail in the up position. When the upper cancel pneumatic is activated (hammer rail down—tracker bar hole #2) the attached metal rod sticking forward pushes the wooden hook back and off of its latching surface, thereby allowing the hammer rail to fall back to its normal resting position. The hammer rail rest, with its thick strip of dark green felt, is clearly visible as it extends beyond the otherwise obscuring piano hammers.

(Photograph courtesy of Bob Gilson.)

Top view of hammer rail control in National automatic piano #348. This view, looking down on the two hammer rail control pneumatics, better accentuates how the cancel pneumatic does its job. When the pneumatic collapses the attached metal rod (that appears to stick downward in the photograph but in the piano is oriented horizontally) moves toward the upper part of the wooden hook. When it contacts the hook's sloping surface the hook is forced to back away from its latching surface. Once the hook has been disengaged, the hammer rail function has been effectively canceled, and the hammer rail falls back to its normal rest position.

(Photograph courtesy of Dana Johnson.)

Hammer rail control in National automatic piano #7524. In this view the hammer rail lock and cancel pneumatics are seen at a distance, which puts them in context relative to the rest of the piano. The rust tarnished wire that connects the lower locking pneumatic to the hammer rail is clearly visible. The two pneumatics and wooden hook are functionally identical to the example shown previously above, although the dimensions and relative proportions may vary slightly. And the hook is not felted in this unrestored piano. Also note that the rubber cloth on the upper cancel pneumatic is split, with its upper movable leaf freely sticking up at an angle, the tip of the pneumatic and the rod that disengages the wooden hook cutoff by the edge of the photograph. The electrical socket and light bulb (to the left of the hammer rail control pneumatics) is placed behind the tune selection number wheel, which displays an illuminated number representing the tune that is being played. Notice that the tune wheel has a cast iron support structure, instead of the fabricated steel framework more commonly found.

(Photograph courtesy of Dana Johnson.)

Sustaining or loud pedal pneumatic in National automatic piano #7125. Covered in black rubber-cloth, the pedal pneumatic is only partially visible, it safely secluded behind the left side stack foot and amidst the clutter of rambling rubber tubes. Can you find it? Its location is within the red trapezoidal shaped box. The sustaining pedal operation is quite simple: The pneumatic collapses, lifting the piano string dampers, whenever the pedal's chain perforation opens tracker bar hole #69 to atmospheric pressure. Once the chain perforation has passed, and hole #69 is closed off again, the pedal pneumatic relaxes, allowing the piano string dampers to return to their normal rest position on the piano strings.