The piano back is composed of a number of vertical wooden posts, extending almost the full height of the piano, which are braced by other horizontal pieces top and bottom. This framework is jointed and glued together in various ways, each method aimed at attaining the greatest structural support possible from the materials used. Woods used for piano backs include pine, spruce, and ash.

The metal plate is a gray-iron casting with tremendous compressive strength that is needed to withstand the enormous overall tension of the strings. An additional desirable property of gray-iron is its damping ability (the ability to absorb vibration without movement or transference of sound, such as ringing). Gray-iron also exhibits high resistance to metal fatigue.

The tuning-pin block (wrest plank) of a vertical piano extends horizontally across the upper framing of the wooden piano back and is securely glued to the latter. The tuning-pin block, made up of several or many laminations of hard rock.