Building a Piano

While it’s true that all pianomakers have their own unique processes and designs, this brief tour features some of the critical steps in the construction of a modern vertical piano.

Each year, approximately 100,000 new pianos are manufactured and shipped for consumption in the U.S. by individuals, institutions, professionals, performing arts organizations and commercial establishments.

Compared to most products we buy today, pianos still require considerably more time and skill to complete. After the harvested logs leave the mill pond, they are classified and then processed at the lumber mill. The sawn lumber is then stacked and slowly dried and seasoned for maximum stability. Thus, considerable time, investment and resources are consumed before the piano even begins to take shape. As the lumber begins to pass through factory operations it will continue to be trimmed, planed, routed, sanded, seasoned and finished as the piano passes through its various phases of construction.

But first the lumber must be properly dried in heated, climate-controlled kilns. This ensures maximum stability which allows the piano to perform year after year with only routine maintenance. The manufacturer determines and measures the correct moisture content of the various wood parts. It is here that imperfections and defects are most likely to become apparent, and avoided. This is one of the reasons a piano can truly be considered a “lifetime” investment.

One of the most critical components of the piano is the soundboard, the tonal “heart” of the instrument. Here, the wood planks that will be edge-glued together are first carefully assembled as the soundboard outline begins to take shape.

The planks which make up the soundboard are then glued together and left to dry and “season”. Next, it is trimmed to a size which is close to its final dimensions, when it then becomes part of the piano.

Before a soundboard can “speak” with rich tone and with volume, the wood fibers must be stretched. This is achieved by bending the soundboard or “crowning”. A series of ribs are glued to the back side to support this curvature, or “crown”. The soundboard is then mounted on a wood “backframe”.

Sound is transmitted to the soundboard by the vibrating strings through bridges, over which the strings are stretched. The bridges must first be notched, which allows the strings to be cleanly “seated” which eliminates buzzes and unwanted harmonics.

The front of the finished soundboard shows the “pinblock” which holds the tuning pins in place (mounted at the top), as well as the notched treble and bass bridges.

The back of the piano clearly shows the backframe with soundboard and ribs which support the soundboard crown.

The strings, usually numbering about 220, will exert an enormous amount of tension when tuned to pitch. To resist this, a rigid cast iron “plate” is mounted to the soundboard/backframe assembly.

A hole for each “tuning pin” is precast in the iron plate along with “pressure bars” and “hitchpins” to guide and anchor the strings.

After the plate is mounted, holes for the tuning pins are carefully drilled into the pinblock, guided by the holes in the plate. Thus, accurate placement of the plate is critical.

Next, each pin is gently driven in to an exact height through its hole in the plate and into the pinblock. Each steel tuning pin is slightly tapered and has fine cut threads to help the pin grip tightly.

Once the pin is “seated”, it will be very tight. This holds each string in tune between tunings, done by a qualified piano technician.

The backframe assembly, with the soundboard, plate and pinblock with pins installed now moves on to the stringing department

A skilled “stringer” chooses the correct string gauge (thickness) for each pin. Every string end is wound around the top of the tuning pin exactly two and one-half turns.

The first few initial tunings are done with the strung back lying horizontally. These are not very precise tunings but are intended to gradually bring the piano up to pitch. These are called “chip” tunings. Later, the piano will be fine tuned.

The completed strung backframe will now be allowed to sit idle for a while to stabilize before another series of tunings. Each manufacturer designs its plate and string layout differently for each model. This is called the scale design.

Pianos are, of course, also admired for their beauty. As the musical portions of the instrument are being constructed, another part of the factory is producing the furniture in which the instrument will be housed. Scores of sizes, shapes, styles, colors and finishes are produced in today’s modern piano factories around the world. After the component parts are cut, trimmed, milled and sanded they are ready for finishing.

There are many steps in the wood finishing process. Case parts for an individual piano travel together in the finishing process so that they will be well matched, and also to ensure that all components are present for final assembly.

The final steps in the finishing process bring out the rich natural beauty of the wood. The strung back, which has been stabilizing and receiving chip tunings is now ready to be fitted with the finished case parts.

In still another place, the piano action, keys and hammers are being produced. With over 10,000 individual parts, the action is without doubt the most complex part of the piano. A block or bat of highly compressed felt is trimmed to the desired hammer shape before it is sliced into individual hammerfelts.

The finished hammers are then wrapped and glued to a wooden hammer core. The hammer and core are then mounted on a small wood dowel called a “shank”. The entire assembly is the mounted on each of the 88 action sections, one for each key.

The piano keys are likewise sawn into 88 sections from one continuous wooden slab. The white and black keytops are carefully glued and trimmed to the proper dimensions before installation into the piano. Keys may be inserted with lead weights as needed to balance the keys for responsive touch and uniformity.

The piano action receives many adjustments before the hammers and the keys are installed. Height, spacing and alignment are all checked and rechecked to make sure that the musical portion of the instrument performs properly.

The keys and hammers are then installed in the piano.

This begins another series of many fine adjustments which is called “action regulation”. Regulation takes a skilled, qualified technician and should be checked occasionally throughout the life of the piano.

The finished piano action is truly a marvel of precision and innovation which was accumulated over a period of three centuries. Remember, there are 88 sections just like this one in a finished console piano!

The piano is now almost ready for shipment. First, it will receive one more fine tuning before final inspection and crating.