Bechstein IV Upright Action Issue: Unnecessary Contact Between Hammer and Damper

[themaximillyan]

Bechstein IV Upright Action Issue: Unnecessary Contact Between Hammer Felt and Damper.

On a 1900s Bechstein Upright piano, there is an issue within 'the action' where the hammer fails to strike the strings when an adjacent key to the left is already depressed. This issue affects approximately a one-octave range. The video demonstrates the indentations present in the hammer felts caused by the corners of the damper heads.

Attempts to lower the damper have been made; however, due to the overstrung angle, the damper becomes misaligned from the strings, resulting in inadequate dampening of the double string. The proposed solution involves further trimming (shave of) the bottom corner of the hammer felt where it comes into contact with the damper head.
It is possible that 'Bechstein' utilized an unconventional hammer felt shape in these pianos. When replacing the hammer felts with the standard shape, this issue may arise, especially if a slight groove has formed in the felt from the strings, causing the hammer to come into contact with the damper stop, thus restricting its movement compared to the initial fitting process.