Abstract: A universal piano action having a minimum number of identical parts interchangeable in upright and grand pianos, under and above the tensioned strings and effecting rapid repetition in upright and grand pianos, this universal piano action responds to every strenght of touch evoking sounds from a whisper to thunder. In this universal piano action the hammers can be positioned to any at rest position, to any proximity in respect to the tensioned strings for a sensitive control of sound, permitting practice playing with a normal strenght of piano key touch without disturbing.