The Part of the Piano that Transforms the Movements of the Fingers into Movements of the Hammers ActionFunction and Construction
• This mechanism converts the action of the fingers striking the keyboard into the movement of the hammers.
• The action for one key has over 60 high precision parts. For 88 keys that is a total of nearly 5500 parts.
• The flange connects each important part and becomes the centre of movement. The inside of the flange hole has been finished with bushing cloth, so that the centre pin inserted into that hole can rotate freely.
• The action determines the touch and the feel of the piano. The touch also affects the psychological impression of the sound quality.
• From rapid trills and note clusters, to slow sustained and expressive playing, the action affects the overall expression of every piece played. In addition, a touch that is sensitive to the actions of the fingers also affects the dynamic range.
How the Action Operates• The force with which the fingers strike the keys is then transmitted to the hammer until finally the piano string is struck.
• Gradually pressing down a key causes the capstan button to push up the whippen. The force then begins to push up the jack.
• After the key has been depressed approximately 5 mm, the damper spoon comes into contact with the damper level, and the damper is release from the string.
• When the key is further depressed to approximately 7 or 8 mm, the jack tail comes into contact with the regulating button, and the end of the jack begins to move so as to disengage it from the butt.
• Since this process is carried out very rapidly, momentum is imparted to the hammer, with which force it then strikes the string. At that instant the key has been depressed as far as it will go. The hammer then rebounds from the impact with the string, and is then received and stopped by the back check.
• When the key begins to move up again, the hammer is brought back to its former position by the action of gravity, the hammer return spring and bridle tape. The damper also again makes contact with the string, dampening any string vibrations . By the time the key has risen to the very top, the entire mechanism has been readied again for the next cycle.
Major Points
Materials• The action must be capable of withstanding many years of strenuous operation. It must not be easily affected by either temperature or humidity changes.
• The main material used in making piano actions is maple. Its seasoning is a careful process using highly advanced techniques. Yamaha is capable of producing incredibly precise and durable piano actions.
• For the centre rail, which is the foundation of the entire action, Yamaha was the first in the world to use an aluminum alloy material instead of wood. It is highly resistant to the effects of humidity changes and deformation of any sort. This insures that the string impact position of the hammers remains extremely stable.
• Jacks and capstan buttons made of wood are prone to wear, which has an adverse effect on the touch. Therefore, in these areas, Yamaha uses high quality ABS Resin which is temperature and moisture resistant and is extremely durable. The material is very resistant to torsional and surface deformation as well, insuring that the piano will keep a smooth touch for a long time.
• The bushing cloth affects the movement of the centre pin and therefore the touch as well. For this purpose, Yamaha uses a special cloth which is well fitted to the centre pin, aiding in smooth action operation.
• The action must be capable of reacting sensitively and precisely to the movements of the performer's fingers. It must also be capable of maintaining a high standard of performance for many years.
• Yamaha always solicits the opinions of foreign and domestic pianists and musicians, and is always researching a piano that will bring out the touch most sought after by the best pianists.
Fabrication Technology• All parts of Yamaha piano actions are produced in-house. Thus, we insure that the finished product follows the original design concept as closely as possible.
• Assembling the piano action into the piano itself requires highly skilled technicians and specialized techniques. A fine sound cannot be produced if the precision of either the action or the piano itself is insufficient. A deviation of 1 mm in the string impact position can adversely affect the overall sound.
• In producing the flange, which is the pivot of the entire action mechanism, very strict machining stands have been employed, finishing the final product to precision with 5/ 100ths of a millimeter.
• Each part of the action, including the flange, is produced using Yamaha's in-house developed and specialized precision machinery.
• The JIS standard for piano actions dictates that the string impact test must cover 200,000 impacts. However, Yamaha's string impact test involves 300,000 impacts far greater than that of the JIS standard. This far more stringent standard has been accepted as our reference.
