The mechanics of a grand action are brilliant, a series of levers that reaches inside the piano while converting finger force into a hammer force that can play strings with musical expression. Such a feat has many complicated details, but observed individually, they are logical, pragmatic – mechanical. Geometry is the design engine for this collaboration. And its leverages both transfer these forces and transform the distances they travel. Each finger’s mechanical advantage (2 kilograms to play a 10-or-less gram hammer) is divided by 5 in a tradeoff multiplying finger travel distance by 5 into a hammer travel distance that accomplishes fff. Or ppp.
How do we become professionally conversant with the things we think we know? Experience will prove or disprove many details over time but without a concerted effort (and a bunch of time) these are hard to consolidate into an overall and useful understanding. Over and over, I have observed the action tradeoff between distance and weight, but how clear am I on the full implications and applications of this relationship? A simple model might help.