Shhhh, don't tell Yamaha! (actually its ok, I'm authorized for Yamaha service)
Obviously I did this as part of the article I'm writing for the next edition of PB, and its not like I haven't been inside plenty of instruments, but one detail in particular just blew me away and I had to share.
- unedited by the punctuation police
One internal detail that I found fascinating was the construction of what is referred to as the shank stopper. The hammer heads do not actually strike anything. Instead, the hammer's upward travel is stopped when the hammer shank contacts the shank stopper at a point just below the hammer head. The first thing I noticed about it was that the width of cushioning material that the shank contacts is tapered from the bass to the treble; being roughly twice as wide at the bass end. The cushioning material is comprised of two layers of material with the top layer—the one actually struck by the shank—softer while the lower layer is more dense. The core of the shank stopper is wood but it is stiffened with metal side panels, then covered on top with heavier metal plates to add mass. Clearly this was not done in the interest of cost, but to maintain the proper feel of the action even though this piece has only the briefest influence on the hammers rebound feel. Resilience, stiffness, mass; I wonder how many variations were tried before arriving at this combination?
- end
And yes, there's a real grand action in there.
Back to work...