Escapement is the adjustment on a Rhodes piano a that determines the height of the harp in relation to the action, specifically the hammer. It is a key factor in determining the touch and weight of a piano action, and can have a profound effect on the way the piano is set up and played.
It is called escapement because it is necessary to have a gap between the hammer tip and the tine after the key is pressed and the hammer is in stop-lock position. This is necessary to allow the hammer to fall back away or ‘escape’ away from the tine to allow the tine to vibrate and the tone bar assembly to sustain. It is a similar but simpler concept to let-off in Wurlitzer and acoustic pianos.
Function:
As described above, escapement is essential for a tine to vibrate and generate a tone. Without it a note would choke and stop instantly. Ideally escapement would be the same throughout the whole piano, but because bass tines are longer and therefore have a greater vibrational movement the escapement needs to be higher in the bass. This makes the bass of a rhodes piano generally feel heavier than the treble, which conveniently emulates the touch of acoustic pianos where the bass touch is also heavier.
Measurement:
The escapement distance is calculated by measuring the gap between the hammer tip and the tine at each end of the piano when the hammer is in stop-lock position. This is done in three places: the extreme bass, tone bar 41 in the middle, and the extreme treble. The ideal escapement settings according to the Rhodes service manual are shown below.
Adjustment:
Escapement can be adjusted in two ways: the individual adjustment of the escapement screw on the tone bar (1), and by adding or removing shims at either end underneath the harp where it connects to the harp support brackets (2). The escapement screws of each tone bar should be set at the same height. This is usually 3/8”, but can be adjusted to personal preference.
Once escapement of all tone bars is even general adjustments can be made by the adding or removing of shims. The process this is quite straightforward, though a significant adjustment in height will require the piano regulation to be adjusted. In particular the damper adjustment and potentially strike-line are the aspects that can be affected.
Issues:
Over-adjustment of escapement either via the escapement screws or shims can lead to problems:
If the escapement is too low then hammer tips can choke or kill the sustain of a note. This can also happen if the damper does not clear the tine. The lost motion from the damper arms can also be too much, making the action feel too light.
If the escapement is too high then the damper felts may not dampen the tines properly, causing notes to ring out or sustain when the key is released.
