A damper grommet is a small circular rubber grommet found on the damper regulating screw of each note in Wurlitzer pianos. It is either black or grey in colour, depending on the model of Wurlitzer and year of manufacture. It inserts into a the damper lever clip found on the damper arm.
Function:
The grommet’s function in the action is to act as a connector between the whip assembly and damper arm. When the key is pressed the rear of the whip is pulled down, which then pulls the damper rod down. These rods are also known as stickers. The damper screw is connected to the rod, and pulls down on the grommet. The grommet then pulls the damper lever clip. Pivoting through the damper flange, this raises the damper felts which causes the reed to sustain.
The grommet is necessary because it acts as a housing for the damper screw, allowing the damper to function. The material, a hardened rubber, allows it to perform the role of transferring movement without adding extra friction or noise. If a note is clicking or knocking, checking the damper grommet is a good place to start.
Servicing:
The damper grommet is also allows the damper arm and whip assembly to be disconnected from each other. This is very helpful when removing the entire damper mechanism to perform work on the hammers or reed bar. The grommets unclip easily, but take care not to pull too hard to remove the damper lever clips.
For proper function of the dampers, the head of the damper screw should be raised above the grommet. This is so the damper felt is always resting on the reed. According to the Wurlitzer service manual this should be 0.035” or 1mm approximately, but adding a little more space can ensure all dampers are always seated on the reeds at rest position. Crucially, no reed should sustain when the note is released, unless of course the sustain pedal is pressed. The damper screw adjustment is linked to lost-motion, and can make the key feel somewhat lighter when played.
Replacement:
Older grommets can start to create friction and noise into the action. If this is the case then they should be replaced. Removal of the grommets requires removal of the damper regulating screws. This can potentially cause the stickers to break creating much more work. Therefore it is only recommended to change damper grommets if it is absolutely needed.
