Why Does the Jack of the Wippen Get Stuck in the Hammer Butt of an Upright

[maxim_tuner]

https://youtu.be/bJXgqcrWHBY

• Description:
  Encountering a stuck key on your upright piano? The issue might lie in the interaction between 'the jack of the wippen' and the hammer butt. When depressing a key, 'the jack' can become lodged on 'the hammer butt', a component typically covered in dark beige felt. This occurrence stems from the jack failing to clear the leather of the hammer butt during the mechanism's 'let off' phase at the end of a keystroke.
  
  The jack, a plastic part of the upright piano action, is designed to move freely from the hammer butt's leather surface during operation. However, it may not travel far enough due to two potential issues: the 'let off' setting being too close or the keys sinking, resulting in inadequate key travel.
  If the 'let off' is not excessively close, the issue likely lies in regulating the jack itself. This involves ensuring the jack is in optimal working condition, which may entail minor adjustments. Additionally, lightly unscrewing the 'let off' from its from wooden plank can provide the necessary clearance for the jack to move freely without obstruction.
  
  By addressing these factors, 'the jack

' can function properly, restoring smooth operation to your upright piano.