The Complete Handbook of Pianos

Chapter 1: Understanding Pianos

A piano is a stringed percussion instrument that converts the mechanical motion of keys and hammers into sound through the vibration of steel strings and a wooden resonating board. Unlike guitars or violins, where the player controls the string directly, a piano player controls a complex mechanical system—the action—that strikes the strings with precision timing and variable force. The three major systems that define a piano are the action, the strings, and the soundboard. Understanding how each works, and how they interact, is essential to evaluating any piano, maintaining it properly, and knowing what you are actually paying for.

The Action: Converting Key Motion into Hammer Strike

The action is the mechanical assembly that connects the keyboard to the hammers. When you press a key, you initiate a sequence of precisely timed events that must complete in less than half a second. Here is what happens physically:

A piano key is a lever. Pressing the front of the key raises the back, which is connected to a wooden rail called the wippen. The wippen is attached to a jack—a small wooden or plastic piece that rests under a curved surface called the hammer butt. As the key descends and the wippen rises, the jack pushes upward, propelling the hammer toward the strings at increasing speed. The faster you press the key, the faster the jack accelerates the hammer, and the harder the hammer strikes the strings. This is how pianists control volume: not