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Rebuilding the Damper Mechanism of a Chickering Grand Piano

The project described below was recently completed on an 1918 Chickering Grand Piano. Besides cleaning and lubricating the wires and centers, we addressed two main problems: (1) The old damper pads no longer did their job well: a few were missing, and several had become so hard and brittle that they caused metallic noises when they were lowered over the strings upon releasing the keys. We decided to install new damper pads. (2) The original underlever flanges held the wires through threaded screw-holes--this made it very difficult to remove the dampers and would also result in complications with re-installing and regulating them.  We decided to convert the flanges by installing set-screws on them.

1918 Chickering Grand --"Regulating Damper Underlever Heights"

19 - After the flanges have been converted to include a set-screw for the damper wires, we were able to install the dampers after stringing the piano. We then regulated the underlever heights so that the keys would lift the dampers half-way through the key stroke. We used the "Spurlock Underlever Height Guide" to ensure that the underlevers were all set at the same heights. This process was greatly facilitated by the conversion of the damper flanges.

1 – Since the damper wires of this piano were screwed into the flanges, making it impossible to remove the dampers singly, we propped up the dampers while removing the strings.

2 – Dampers propped up--view from above.

3 – In modern conventional grand pianos, the damper wires are usually installed in the flanges with set-screws. In order to make the dampers easier to install and adjust, we "modernized" each underlever flange by gluing a small damper block with a set-screw on top of it, reinforced by a strip of veneer. The following pictures describe the process we used.

4 – After numbering them, we removed four flanges at a time, cut a thin layer of wood off the tops to leave a flat surface, and we re-drilled the damper wire holes a larger size so that the threaded ends of the damper wires would travel freely through the flanges when installed again.

5 – Using a jig on our belt sander we sanded the cut-off top edge of each flange so it was perfectly flat.

6 – The "extensions" that we added to the flanges are actually straight treble damper blocks usually found in upright pianos. With a nail in the holes, we tightened the set-screws; then we drew a line on the damper block to show where it should be cut.

7 – Using a home-made jig to hold the damper block and flange in place, we cut the damper block on our band saw.

8 – We lightly sanded the cut edge to ensure that it lined up with the back of the flange.

9 – We cut a number of small pieces of veneer to use for reinforcement at the back of the block and flange, then spread glue on all surfaces to be assembled.

10 – We clamped together the flange, block, and backing-veneer on a flat board.

11 – While working on the next set of four flanges-and-blocks, we gave the converted flanges about 1/2-hour to dry.

12 – We sanded waste veneer off the back edges of the converted flanges.

13 – With the converted flanges installed in the damper underlevers, we will be able to restring the piano before re-installing the dampers, and we will be able to regulate  dampers using the new set-screws for adjusting the heights.

14 – Using larger-size center pins, we re-installed the converted dampers onto the underlevers. At the rate of about four per half-hour, it took us two days to convert all 66 flanges, but we feel it was well worth the effort in improving the functioning of the damper action.

15 – The entire set of underlever flanges has been converted and re-installed.

16 – We cleaned the damper wires and installed a new set of damper felts.

17 – We installed a few dampers to test the accuracy of the converted flanges and of the sostenuto mechanism. Before installing the plate, we removed these dampers again. We also removed the bass damper guides to leave plenty of room for the plate.

18 – After stringing the piano, we re-installed the dampers.