When you seek to be unique...

A couple of questions about very unique pianos:

1. KawaiDon spoke in the thick/thin rim thread, about kicking around with pianos made from various species of wood, and testing the acoustical properties.

What happens to a manufacturer's experimental pianos? Is there a guy out there somewhere with a catalpa rimmed Kawai? Or an ash rimmed Steinway?
Or a Yamaha C with an MDF case?

2. Also noticed that our new member Del, will custom-build a piano for you. (I would assume using components sourced from where he can obtain them)

When custom-building a piano, can one specify scale, finish, keytops, string brand, etc.? On the other hand, I would assume some combinations work much better than others, so what does one do, describe the tone wanted, and then turn the pianobuilder loose?


Inquiring minds.....

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1) I can't speak for others but while I was at Baldwin they were scrapped. Or, if the modifications made for a particular experiment did not alter the basic structure, they would be taken back to the point just before they diverged from production standard and finished out as normal pianos and sold.

2) In our case building a custom piano is just like building a prototype. Within some practical limits — and the limits of my opinions and experience and general stubbornness — you can have just about anything you want and can afford to pay for.

That includes the size of the piano, its scaling, its projected tone qualities, etc. We would build a simple rim press to form the rim — the expectation is that these would be one-off instruments. The plate can be either built-up structural steel or cast gray iron depending on your preference and/or the depth of your pocketbook. Casting patterns are expensive, the casting itself is relatively cheap.

The scaling is chosen to best produce the type of voice you want the finished piano to have. There are some things I won't do if I know from experience they won't work but otherwise it's open season.

There are some components we prefer to use by choice, but as long as the customer is willing to accept responsibility for the final outcome we will use whatever alternatives the customer is willing to pay for.

We do not currently employ a custom cabinetmaker, but many are available in the region. Again, as long as the customers wishes do not adversely affect the ultimate performance we will build whatever the customer wants as long as we can locate the materials and a craftsman to do the work. (One exception—we will not use woods that come from trees on the brink of extinction. We prefer to use woods available from certifiably sustainable sources. Obviously we make exceptions — there are no certifiably sustainable spruce forests. Yet.)

You can have pretty much what you want in terms of keys — as long as one of the keymakers can make them. Ditto actions. We hold some pretty strong opinions on hammers. And soundboards.

The best approach would be to work together to establish the basics — size, general shape, desired tone quality, cabinetry, etc. — and allow us to work out a proposal and rough sketches. Once that is created the details will pretty much take care of themselves.

I should say that other than ourselves and one manufacturer no one has yet taken us up on this. We keep hoping — I have the basics of several interesting grand and vertical piano designs sitting around in my computer.

Del

Oh, you're gonna fit in really well here!

Hmm, that's interesting. Structural steel? You mean like regular old "A36" structural steel? I thought that steel didn't have acceptable damping qualities (pardon if this is not the correct technical term) that a good plate material should exhibit, compared to cast iron. Could you elaborate?

Hmm, that's interesting. Structural steel? You mean like regular old "A36" structural steel? I thought that steel didn't have acceptable damping qualities (pardon if this is not the correct technical term) that a good plate material should exhibit, compared to cast iron. Could you elaborate? [/QB][/QUOTE]
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What is meant by exactly "acceptable damping qualities? This is the character of gray iron that always comes up in this discussion. It has been promoted for decades as a desirable thing. But why on earth do we want the piano plate to have “damping qualities?” Gray iron is used for industrial machine bases because it readily absorbs vibrating energy. By definition this means that the material readily absorbs and converts vibrating energy into heat. Personally, the last thing I want the piano plate to do is absorb and convert into heat vibrating energy that could be going into acoustical energy.

Yet, whenever this subject comes up I hear this argument. It has been proposed since time immemorial by piano makers and by piano technicians as a desirable thing. Yet very few have actually have had any hands-on experience with steel plates. I have. All prototype pianos at Baldwin were built using plain, off-the-maintenance-room shelf hot-rolled steel stock. My piano plate drawings were converted to accommodate the standard available thicknesses and the plates were welded up in the maintenance shop. Some grinding and hole drilling later and we were ready to build a piano. No, they were not at all pretty but they worked. Indeed, they worked so well that, without exception, generally sounded better than subsequent pianos of the same design using cast gray iron plates.

True, there is a hypothetical problem with braces ringing at some odd harmonic but I never found this to be a problem in real life — we never once had a ringing problem. Which is not, of course, to say that it couldn’t happen. It even happens occasionally with cast gray iron plates. But if it does there are simple and attractive ways to deal with the problem.

The structural advantages of steel are obvious. The tensile strength of the common gray iron mix used to pour piano plates is around 24,000 to 26,000 psi. I don’t recall the exact specification off hand, but I think even hot-rolled steel is about three times that. With various cold-rolled steels it’s pretty easy to get into the 100,000 to 150,000 psi range. Much is made of the supposedly great compression strength of gray iron and it is true that this is somewhat higher than its tensile strength — typically about double for the grade of iron used in piano plates, not enough to make it strength-competitive with steel. So even here it loses out to steel by some considerable margin. Finally, much is said about the supposedly great rigidity of gray iron. But this is a mis-understood phenomena. What gray iron really has is a lack of plasticity. It will bend fairly readily up to its proportional limit — then it breaks. Catastrophically. Steel is both stiffer and lacks this rather nasty habit of breaking like a dropped glass or piece of chalk.

All this aside — actually, because of all this — steel simply makes an acoustically superior piano plate. Perhaps its most significant acoustic advantage over gray iron is a marked and measurable increase in sustain time. Its primary disadvantage is not any tendency to ring, but its cost. Steel plates are decidedly more expensive to make, especially in high volume where cast gray iron shines. Fabricating a built-up steel plate takes time and man hours. It is more difficult to drill — the graphite in gray iron makes this easy — and to finish. Though automation and high production can definitely narrow this gap. They also look a bit unusual since the longitudinal struts are rectangular and do not have any draft. This could be machined in but it would be fairly expensive.

Del

Years ago I moved a piano for a pattern-maker. He said that he thought that forged steel would make a superior plate, stronger and lighter in weight. After reading Del's comments, I can see that would be possibile, even desirable, but it would take a manufacturing facility that would be so different from what is used now that it isn't very likely we would ever see such a thing.

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Perhaps not. But we have seen cast steel plates. The Steinway plates bearing the lettering "Steinway Steel Casting" (or some such) were actually some alloy of steel.

The problem with steel castings as complex as a piano plate is that the steel doesn't flow very well. They are difficult to pour and the scrap rate is fairly high. At least with traditional pouring technologies.

Del

As I recall, the barless plates that Broadwood used were also steel.

Of course, except for some exotic exceptions, all plates are made of an iron-carbon alloy. At some point in the spectrum there is the division between what is called cast iron and what is called steel.

I was imagining a plate that started with two pieces of plate steel, one forged and punched into the portion of plate with the hitchpins, the other into the portion around the tuning pins. The bars, including the capo bars could be welded between them. It could be a practical method of manufacture.

Heh, let the games begin. I always wondered about steel being a better material for plates based on higher tensile strength, less material/weight necessary, and in the (far less likely than with cast iron) instance of one cracking, greater ease in repair. But I had always heard that the acoustical properties were less desireable. As Arte Johnson would say, verrrrry interesting...

Generally, steel contains anything from 0.1 up to 2 wt% carbon, while cast iron (white and grey) typically contains 2-4 wt%C. Cast iron is the cheapest metallurgical material available to the engineer as it is simply re-melted pig iron. Steel is produced only after pig iron is refined.

I expect it could be. We've had this mindset about cast gray iron for close to two centuries. It's not going to change overnight. Very few piano makers have even considered anything else. Before the bankruptcy of Baldwin United some consideration was given to using built-up steel plates in the vertical piano line. Their studies at the time suggested that at some level steel would be cost-competitive with cast gray iron. I might note that vertical plates are much cleaner and simpler to design and build than are grand plates.

Del

With regards to manufacturing the plate from steel, a few years ago, some colleagues of mine were researching the possibility of building up complicated metallic parts using a sort of spray-casting method, whereby drops of molten metal could be sprayed on layer by layer into the required shape using computer control. This was known as rapid prototyping. The whole idea is to allow manufacturers to increase flexibility in terms of the types of parts produced, decrease lead time from design to production, as well as have the ability to produce small batches at lower cost. Perhaps successful technologies developed in this area will one day find its way to piano-makers!

Perhaps. But I'll not be holding my breath. The most recent change — the only one since Babcock, actually — in piano plates came with the introduction of the so-called V-process in which dry sand is held in place with a plastic film and vacuum. And this process was not adapted by the piano industry because it offered any acoustical advantage but because in very high production it reduced the cost of the finished plate.
There are several developments in materials and casting I would like to see explored. Just an increase in the tensile strength of the iron used would be of some benefit all by itself. Beyond this it might be beneficial to explore the use of ductile iron or malleable iron. The “no-bake mold” offers the potential of much greater dimensional control compared to green-sand casting but does not require the high tooling costs of the V-process.
It is unlikely that any of these, let alone any really modern, high-tech casting technique, will find its way into the fabrication of piano plates any time soon unless it can be shown to reduce the cost of the plate or unless the buying public begins to demand an improved product. And, unfortunately, we are simply not doing that. Well, indirectly we are. Piano sales are continuing their downward spiral. But the industry attitude is still, “good enough is good enough so let’s not rock the boat.” Or, in this case, the plate.

Del

Del, you said,
Does this mean you exclusively use only one kind (Abel)? What's your criteria for a superior hammer?

(By the way, it's a great pleasure to have you on the Forum!)

-Jimbo

We did use Abel hammers on our uprights. We designed them and specified exactly what we wanted and pretty much got that. They were purchased directly from Abel. We do not use Abel hammers purchased from U.S. suppliers, finding them far too dense and hard for our needs.

We prefer cold (or warm) pressed hammers and usually use either Isaacs or Ronson hammers.

Del

It has been very interesting and very educational to read Del's discussion on piano design. (I thank Del for generously sharing his knowledge.)

I am very curious, how many practising "Piano Designers" are there today, in the US, in the world? How does one become a "Piano Designer" ? I cannot recall any college/university offering any course that teaches "Piano Design." Is it a combination of mechanical engineering plus decades of apprenticeship in a piano building workshop? Is the demand for "Piano Designers" out-stripping supply currently? I have no ambition to become a Piano Designer myself, but I am very curious how some one could become a Piano Designer and the market dynamics governing this profession. Thanks for any insight you care to share.

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There are four or five independent piano designers in the world that I know of. There may well be a few more — there is no network that keeps track of these things. The number depends, I suppose, on how you define “piano designer.” Perhaps only three or four of these have actually designed and built either a vertical or a grand piano on their own. There are others who are probably knowledgeable enough but who have not yet actually done the deed.

There are several larger factories that employ design and engineering people as part of their permanent staff. Among the most creative of these currently is Schimmel. I may not much like what they are doing but at least they are doing something!

No, there are no schools that teach this stuff. I can only speak for myself, but I learned mostly by doing. I started as a piano technician and rebuilder who got frustrated by the consistent problems encountered in both new pianos and those I was rebuilding. I began to study a variety of subjects that taught me what I needed to know about vibration analysis and structural analysis to get by. The rest I learned by trial and error and by thinking. By setting pencil to paper and building it. First at my expense and then at Baldwin’s expense.

There is not a high demand for piano designers. Mostly I think the industry would prefer that we all go away and leave them alone. I’ve been fortunate in that I was able to work at Baldwin during a time when I was able actually do a bit of original design work. Plus the experience taught me a lot about production and production problems. Following that I was also fortunate in getting a contract to design a 190 cm grand piano for the Walter company. Since then I’ve been able to work with several companies which do not have their own in-house design personal.

I've not had any apprentices since I started doing design work. In part because few seem interested in doing the homework necessary. We're kind of into instant results these days. If you can't find everything you need with a quick google search, well, forget it. Besides, I'm not sure I’d recommend this work to anyone who is not obsessed by the irrational need to tilt at windmills. It’s hardly worth the grief.

Del