Late Type 4 Pneumatic Stack
in Seeburg Coin Pianos
Introduced circa 1922

(Photograph courtesy of Art Reblitz)

This and the following photos show the common “late style” type 4 Stack in Seeburg Greyhound #166,043, made in 1928. The valve cover is removed in these pictures. The stack has two tiers of pneumatics and valves, with each valve board mounted horizontally on top of its pneumatic deck. The front board (or “trunk”) has vertical channels that connect the channels in each deck to the bleeds and tracker bar tubing.

(Photograph courtesy of Art Reblitz)

The stack installed in Greyhound #166,043. The single horizontal tube near the left end of the stack is for the coupled bass note found in all little Seeburg 54-note pianos (PGA, L, C Xylophonian, and Greyhound). The five elbows near the lower right front corner are for the five highest notes on the roll, teeing them to notes an octave lower because the piano is missing these notes.

(Photograph courtesy of Art Reblitz)

Close-up of top valve seats. The valves are simple wooden buttons faced with thin leather on both sides, with fluted wood stems. The bottom seats are short brass tubes pressed into the wood, as in a Gulbransen player piano. The pouches are located in the top of the pneumatic deck.

(Photograph courtesy of Art Reblitz)

Back view of the stack, showing the two tiers of pneumatics. The pushrod wires have an inverted question mark shape where they attach to the pneumatic fingers, preventing them from rotating. This allows the tops to be bent slightly to align with the piano action, without the possibility of becoming misaligned if they rotate, as they can in the early stack.

(Photograph courtesy of Art Reblitz)

Front close-up, showing the characteristic screw pattern that positively identifies it as a late style two-tier stack. Some two-tier stacks have finishing washers under the flat head screws, while others have conical countersunk washers. The brass elbows for the tracker bar tubing are installed in the bottom edge of the trunk. Compare this pattern to the early type 3 (four-tier) stack shown in the previous image pane (under Pneumatic Stacks, paragraph 3), with its different pattern of screws around the perimeter of the front board, and a separate top cap.