What’s Up with Down Bearing? The Genius of Rebuilding.

Posted: February 21, 2014 in Piano

Down bearing.  What is it?

That question asks more than you might realize. What is it indeed? No one seems to know. Well, that isn’t exactly accurate. Everyone seems to know, but there are as many explanations in circulation as there are explainers who do the circulating.

The perils of poor design can contribute to drastic failure of the piano's components.

The perils of poor design can contribute to drastic failure of the piano’s components.

The story of down bearing is a mystery. Defined, down bearing is the force felt upon the bridge of a piano, caused by the pressure exerted by the piano wire. Down bearing must be balanced between the force exerted as the piano wire arrives at the front of the bridge with the force exerted by the wire as it leaves the bridge. If too much force is at either bridge pin, front or back respectively, the bridge may “roll” towards the greater force. This can cause problems. The soundboard (which the bridge is anchored to) may develop an indented curve, the bridge glue might fail, or the bridge might crack. From this we learn that there will be force; it will be evident in two places on the bridge, and it must be balanced within a certain range of tolerance. Consider the diagram below. There must be a positive (+) angle on both the front and back bridge pin. While the definition of down bearing is as I have given it, when a piano rebuilder asks, “What is the down bearing,” he or she is asking what the proper angle should be. The answer is not easy to know. I will explain why.


Genius and down bearing go hand in hand.

A technician draws a piano wire across a bridge to demonstrate its path across the bridge.

A technician draws a piano wire across a bridge to demonstrate its path across the bridge.

When someone designs a piano, (let us refer to that person as the architect), he or she will be very exacting in the placement of every component of the piano. It will be the engineer who works out the math, the practical physicist who maps out the actions and reactions which the inherent forces will have on various interdependent parts, and finally, the skilled craftsman who will actually build the piano. Craftsmen will of course introduce an element of risk to the process, so the engineer, with the encouragement of both the architect and physicist, will invent machines which can better manufacture the piano within more exacting tolerances than is humanly possible. The craftsman is thereby displaced if at all possible. But with the piano, the craftsman is still a valuable component of the manufacturing process.

The architect will place his plans in a safe each night, for fear that a competitor will steal his work. The engineer will also place his mathematical calculations in a safe each night. The draftsman will safeguard the blueprints. Less attention is paid to the work of the physicist because, let’s face it, who can understand a physicist? That leaves the lowly craftsman – an artist of the highest esteem, to consider. He works with his hands, his tools and his machines, and after due time, produces a piano that will endure the passage of 75 years, on average.

And the piano grows old.

Enter the rebuilder. He stands by this old piano, grand in its day, broken, ignored, abused and decayed, and begins the long process by which he will restore this piano without the aid of the architect’s plan, the engineer’s computations, the physicist deliberations and cautions, and without the machinery of a distant age. He stands alone, casting his shadow upon the bulk of assembled brass, steel, cast iron, wood and felt, and rubs his chin as he ponders, considers, and plans, until at last he arrives at that question whose answer lies in a crypt no less impenetrable than those of the architect, engineer, physicist and craftsman…

“What is the down bearing?”

A technician measures the crown of an inverted piano soundboard.

A technician measures the crown of an inverted piano soundboard.

For the so0undboard has lost its crown, and thus the bridge has lost its height, and the angle has lost its degree, and whatever the down bearing might have been, cannot be known. What it should be, is known only to those who have long since passed. Down bearing is a mystery.

Mysteries however leave clues. And as the craftsman ponders, he begins to parse the clues and unravel the mystery. But he will not likely succeed in an exact restoration. Instead, he will employ his artistic methods, experience, and much good fortune, to find the best possible answer that will lend the best result. But he will not wield that answer through science. He will recreate the piano through art.

Here we have science and art, in contrast. And as you think of that place where they meet, I will tell you how to locate genius, for it is exactly where they coexist.

The Methods of Genius

The architect has her schemes and ideas. The engineer has his calculations. The craftsman relies on his wits and common sense. Each actor has his rules, and it is remiss to ignore those of the craftsman. They are numerous, learned from trial and error or from persistent apprenticeship, and they are all based in common sense. I will provide a few of these rules to give you the flavor of what I speak.

1. If you don’t know how to do it, don’t do it. – How many tasks have been ruined by those who had no business trying to fix something? The craftsman knows that you must know what you are doing before you do it. The catch-22 is that we must learn how to do it before we can know how to do it, and learning includes a starting point where you do not know how to do it. So this rule of the craftsman includes a caveat. It is, “If you don’t know how to do it, and you must do it anyway, don’t let anyone know that you don’t know what you are doing.” That piece of advice will get you through your first attempt, but it only works once: people will find out if you don’t know what you are doing.

2. Measure it before you remove it. If you don’t know where it is supposed to go, make sure you remember how to put it back where it was.

3. Number it. When you remove 88 keys, 88 wippens, or 88 dampers, number them so you can put them back in the same order.

4. If it ain’t broke, don’t fix it. Everyone knows this rule. There is a little bit of craftsmen in all of us.

5. Make a jig first. As you remove screws and bolts, insert them into a piece of cardboard that will record their proper location in the piano.

There are hundreds of these rules. Their teacher is experience.


Michelangelo did not first rely on an architect to design a sculpture. No physicist warned of the perils of unmeasured forces upon the granite. No engineer drew up calculations that would direct the hand of the sculptor.  Michelangelo simply possessed a level of artistry that permitted him to create within the tolerances allowed by science. He was the practical scientist, who was able to perform his art to such exacting specifications that no architect, engineer or physicist was needed. We cannot know what went on in his mind, but his works indicate that he was all of these – architect, engineer, draftsman, physicist and craftsman.


I have never played a rebuilt piano that sounded better than a new piano. A rebuilt piano plays better than it did before it was rebuilt – nothing more. A bad piano cannot be restored to become a prize.  A rebuilt piano that was subjected to the hand of an inexperienced rebuilder, which is most often the case, might not play better than it did before it was rebuilt. I remember the words of one young rebuilder, “I have never rebuilt a piano, but I have ruined a few.” Some are sacrificed so others can be saved, I suppose.

But it does happen, if only rarely, that a rebuilder possesses the genius required to restore a piano to its former grandeur.

He, or she, does not need the plan, the math, the drawing or the science; these are all part of the artistic ability of the rare craftsman, and they are but the threads that remain after the mystery is unraveled.

What is the down bearing?

The craftsman knows. He just knows.


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