How Grand Piano Actions Operate

• Pressing down a key will cause the capstan button to push up the whippen, which, in turn, causes the jack and repetition lever to push the hammer to the string.
• After being depressed approximately 5mm, the far end of the key will begin to raise the damper lever, releasing the damper from the string.
• When the key is further depressed (down to 7 or 8 mm), the repetition lever will collide sequently, with any additional movement, the top end of the jack will slide free of the roller.
• When the jack has escaped and no longer contracts the roller, the key will have reached the limit of its travel and the momentum of the hammer will cause it to continue moving until the sting is struck, producing the sound.
• After the string impact, the nature rebound from the string and the weight of the hammer assembly will bring the hammer back towards its former position, where it will be stopped by the backcheck. This readies the entire action for the next keystroke, and in addition, prevents multiple impacts due to the hammer rebounding.
• When the finger is completely raised from the key, the damper will again be lowered, dampening the vibrations of the string.