Amount of parts in a piano. So it is logical that pianos, like all things mechanical, require regular maintenance to perform at their best.
Each string usually holds around 168 pounds of tension, making the total tension of most standard pianos around 18-20 tons.
Amount of strings in a piano. Each note has three strings in the treble, two strings in the tenor and part of the bass, and only one in the very low bass. It varies from one piano to the next.