Don’t get me wrong. As the lady at Steinway Hall said today, there’s 12,000 parts that go into a grand piano. Err, yeah, I suppose. Depends on who’s counting. Marketing, engineering, or accounting? The piano action is an elegant piece of mechanics; lightweight, effective, and durable. Accounting says abut 10,000 pieces go into a Grand Piano, they’re probably correct. Marketing says 12,000 for good measure. Engineering says there’s only about six actual moving parts in an action, from the key to the hammer, and another three for the underlever/backaction/dampening system. Once you start counting adjustment screws, pins, felt bushings, and one to two felt pads per wear surface, the number balloons to 56-74, depending on whose counting and how elaborate/redundant some of the systems are.
Ok, so what do you really have? You have (1) The Key, or lever. This moves the (2) Wippen – really the only custom piece of hardware in the whole action – to which the (3) repetition lever (key return mechanism) is attached. The (4) Jack, an L shaped piece attached to the end of the wippen is essentially the piston that pushes the (5)hammer shank/(5.5)hammer into the string. The (4)jack slides off a cam on the (5) hammer shank and allows the hammer to fall slightly and let the string ring. Releasing the key/lever, the hammer slides across the (6) backcheck, slowing it and preventing unneeded wear. Literally the only two parts in the whole system that move more than 2mm are the initial key press, and the business end of the hammer.
On the back action, the key/lever literally lifts the dampener. That’s it. To conserve movement, the end of the key lifts the (1) damper lever, which moves the (2) damper wire block/(2.5) damper wire, which acts like push rod in an overhead valve engine to push the (3) damper out of the way temporarily.
Most of these parts are attached to the frame, wippen, key, or both. You could simplify the whole operation by removing the wippen, repetition lever and backcheck, along with the damper lever and still have a functioning piano, it’s just that your action would be very clumsy, have a lot of movement and wear much more quickly (years instead of centuries), as well as be less able to repeat notes rapidly.
Doing some quick math, (action 74*88)+(3 strings*88)= 6776 parts. Throw in a thousand parts for the pedal assembly (extremely generous), another thousand for various nuts, bolts screws and washers and another thousand (again, extremely generous) puts you at 9776 parts. Probably much nearer to 8200 individual pieces. Approximately 1000 of the parts are simply fine tuning pieces so that one action reacts to a key press the same way as the rest. Porsche, in the 1960′s and 1970′s had a lot where they would park cars, and beat on the frame with heavy mallets until the body and doors were within spec – they didn’t roll off the assembly that way. Porsche said it added to the car’s charm – engineers from Toyota had never seen anything like it before – they simply fixed the problem in the production line before the car could ever leave the assembly line. I feel this is the same problem with cheaply made pianos.