The key bed is the base layer of wood that the keyboard assembly rests on. It consists of either a fixed or removable action that houses the front rail and balance rail, and thus the balance rail pins and front rail pins. The position of the keys on the key bed has a significant effect on key height, key dip, and thus action regulation. This is especially true on a Rhodes piano where key dip is not set by shims, felt punchings, but by the key bed itself.
For Wurlitzer pianos, shimming (inserting paper wedges) to adjust the keybed is an important part of ‘bedding’ the keybed. This is the process of aligning the keybed so that all the keys are of equal height. Further fine adjustment can be set by adding paper shims or punchings.
