Tag Archives: piano technicians guild

piano restoration: invention certainly accounts for our busy shop and backlog

cllahan piano serviceLetter from John Callahan

We are Callahan Piano – one of the few “Left Coast” Stanwood connections.

It was great to have a small group of installers gather recently after the CA State PTG convention. All Stanwood folks have an open invitation to come and visit whenever you find yourselves in the Bay Area.

We are a fair sized shop specializing in high-end piano restoration – 95% Steinway and Mason & Hamlin.

We are pleased and proud to have four licensed installers working together under one roof – and complete an average of two PTD’s per month. We are a bit different in that we restore for clients only – we do not buy and sell.

Licensed Installers since 2001, we made the decision some time ago not to do an action job without PTD – and that certainly accounts for our busy shop and backlog.

The more Stanwood actions we do – the more folks want it.

When a potential client can visit the shop and play one, and sometimes two or three pianos, all with the same mind-blowing ease and evenness – the decision to have us do their action becomes easy.

Our success over the past few years has been the result of fairly intense marketing efforts to get local pianists and potential clients into the shop whenever we have a completed instrument.

We have also found it very effective to host “send-off” parties on completion of a major restoration. The client invites friends and colleagues, and we supply wine and cheese, and the piano is the star of the evening. Lot’s of fun. (And the biggest plus – it gets the shop cleaned up!).

Thanks to David for all his work which has benefited so many technicians and pianists!

Best regards to all,


John Callahan, Callahan Piano Service

Trip brings piano technician in tune with past

cuba trip

By Julia Wells, Globe Correspondent, Boston Sunday Globe, 02/15/98

WEST TISBURY – The black and white photograph captures three young boys standing in front of a fireplace – sport coats buttoned, hair plastered into place, corny smiles for the camera.

David Stanwood props the picture on the table in the sunny kitchen of his West Tisbury farmhouse. For a minute he is lost in memory.

It was February 1958, and Stanwood was 7 years old, vacationing in Miami with his family. ”My father said, `Let’s go over to Havana for the day,”’ Stanwood recalls.

They visited the Havana Country Club, and during the visit a picture was taken of David and his two brothers in the formal reception room at the club. Behind them, over the mantel, hung a portrait of Frederick Snare, their great-grandfather.

In the early 1900s Snare founded an engineering company that helped build Cuba’s infrastructure. The company built bridges, schools, and the National Baseball Stadium in Havana.

Snare, who loved to play golf, also founded the Havana Country Club in 1911 and was its president until his death in 1946.

Stanwood remembers the day of the visit and how, as the youngest brother, he was the one who had to wear a ”stupid” bow tie.

A year later, the Cuban revolution occurred and the Stanwoods lost all touch with the island. ”My whole life I have had this picture – but we always thought the place was probably gone after the revolution,” Stanwood says.

In July 1996, Stanwood, an internationally acclaimed piano technician who lives on Martha’s Vineyard, attended the annual Institute of Piano Technicians Guild meeting in Orlando, Fla.

While there, he met Benjamin Treuhaft. Treuhaft told Stanwood about a mission he had begun to take pianos and piano technicians into Cuba.

”It was kind of a mission of mercy, as he described it,” Stanwood says. During the conversation Stanwood told Treuhaft that his great-grandfather had founded the Havana Country Club.

”He just screamed and said, `That is where we work!’ He said, `You have to come.”’

In January, Stanwood and his wife, Eleanor, traveled to Havana with 18 piano technicians from all over North America. With special visas from both the US Treasury Department and the Cuban Ministry of Culture, the group’s mission was to work with Cubans on pianos for 10 days.

They brought 25 donated pianos, medical supplies, and 13 bicycles. Officially they were called the Piano Tuners’ Brigade, but at the outset Eleanor Stanwood came up with another nickname: the Piano Peace Corps.

Stanwood admits that the mission was the second reason he wanted to go to Cuba. ”Deep down inside me the real reason I wanted to go was to find out what happened to the country club, to the painting of my great-grandfather,” he says.

The morning after the group arrived, they walked to the country club and gathered in front of the fireplace for the opening reception – the same fireplace where Stanwood was photographed 40 years ago.

”I didn’t say anything. I just took the picture out and put it on the mantel,” he smiles.

The Stanwoods were amazed to find that the country club was unchanged; the furniture was the same, the same two urns stood on the mantel, the same barometer hung on the wall near the fireplace. Like so much of Havana, the room had been frozen in time.

The only thing missing was the portrait of Frederick Snare, which the Stanwoods learned had been taken to the Havana Museum of Fine Arts for safekeeping after the revolution.

”All these years we always thought they had probably trashed the place. I imagined it had been burned in the name of the revolution, my grandfather’s portrait slashed and destroyed as a symbol of capitalism,” Stanwood says.

Instead they found that after the revolution the country club had been turned into Cuba’s first school of the arts, the Instituto Superior de Arte. It is where the country’s most talented artists come to study music, sculpture, painting, dance and theater.

”Everywhere we went, we heard music,” Stanwood says.

Stanwood, whose work takes him all over the world, was struck by the quality of the music he heard. ”I have been on the campuses of music schools many, many times – and what was really different here is you could stop at any moment and listen to a level of music that was really extraordinary. It is the expression, the heart, you can feel the Cuban people, you feel their embrace in their music.”

The Stanwoods say traveling to Cuba was like traveling back in time. All the automobiles are from the 1950s, there are no high-rise buildings, and everywhere people walk and ride bicycles. ”It seems like time stopped in 1959,” says Eleanor Stanwood.

The Stanwoods say the Cuban people have little money and few material possessions, their buildings are crumbling, but they are rich in spirit and culture.

”The revolution is a very clear presence in the minds and hearts of the people,” says Eleanor Stanwood. ”You are not free, there is no privacy. And yet they are very open, very aware of each other. Everyone looks you in the eye and you feel completely safe, even on the darkest street at night with complete strangers.”

”The success story in Cuba is the quality of their culture – it is something they are doing right,” David Stanwood says.

The piano technicians did most of their work in the same room where Stanwood was photographed with his brothers 40 years ago.

Stanwood said there are thousands of pianos in Cuba but only a handful of technicians trained to work on them. Many of the pianos are in terrible condition and there is a widespread problem with termites.

The Stanwoods plan to return to Cuba next year with the Piano Peace Corps; this time they plan to stay for a month and take their two teenage children. The group hopes to establish a school at the institute to train piano technicians with the help of foundation money from the United States.

Stanwood has one other goal – to retrieve the portrait of his great-grandfather from the museum and hang it over the mantel again in the reception room of the old country club.

”That they chose the country club to make it an institute of the arts was the finest tribute to the spirit of my grandfather,” he says.

By Julia Wells, Globe Correspondent, Boston Sunday Globe,

This story ran on page B07 of the Boston Globe on 02/15/98.
© Copyright 1998 Globe Newspaper Company.

The New Touchweight Metrology

Published in  the Piano Technicians Journal, June 1996
Reformatted for HTML internet reading

The new touchweight metrology
By David C. Stanwood, RPT

Boston PTG Chapter


As piano builders and rebuilders, we have inherited a crude and archaic system for measuring the balance of the action mechanism.

The weight of the hammer, which sits out on the end of a long lever arm and has such tremendous influence on touch and tone, is measured in weight to the nearest pound of a sheet of felt from which many sets of hammers are made.

We assume the proportion of key to hammer movement is roughly 1:5, but have no reasonable means for accurately measuring this ratio or detecting leverage problems.  The keys are “balanced” using downweight as a primary indicator but “balance” implies a state of static equilibrium and downweight is taken from the moving key.

We know that when a piano is built, the weight of the action parts sitting on the back of the key exerts an upward force at the front of the key which is too high without the addition of keyleads to the front of the key.
What is the effective weight of the action parts?

How does their weight translate to an upward force at the front of the key?

How much is the downward force at the front of the key?

Conventional wisdom simply does not provide answers to these important questions.

A New System Of Weights & Measures

I have found answers to these and many other questions’ by inventing a new system of weights and measures.  Metrology is the science of weights and measures so I call this system “The New Touchweight Metrology.”

The units of the New Touchweight Metrology define the balance of the upwards and downwards static forces at the front of the key as contributed by the weight and leverage of each action component.

The piano action may seem like a complex mechanism but in fact it acts as a simple lever that propels a hammer into the string. It functions as a catapult, with a short lever arm on one side of a pivot and a long lever on the other. The long lever arm is shortened into what engineers call a “folded beam” by use of the wippen and shank levers.

The New Touchweight Metrology takes the folded beam of the action and “Unfolds” it into a simple balanced lever such as the scale you might find in your doctors office, where:

B = Balance Weight
F = Front Weight
W = Wippen Weight at the Key Ratio radius
S = Strike Weight at the Strike Ratio radius

Figure 1

Figure 2 shows the balance of static forces at the front of the key, where: The downward static force of the Wippen Weight on the back of the key translates through the Key Ratio to the upward force of the Wippen Balance Weight at the front of the key, and:

The downward static force of the Strike Weight is multiplied through the combined leverage of the shank, wippen, and key to the upward force of the Strike Balance Weight at the front of the key.

The balance of the upward and downward static forces at the front of the key are expressed as the equation:

BalanceWt + FrontWt = (WippenWt x KeyRatio) + (StrikeWt x StrikeRatio)

Definition & Determination Of The Units

Balance Weight– The amount of weight, placed on the front of the assembled key that equals the upwards static force at the front of the key.  Balance Weight is found by measuring UpWeight and DownWeight and

Balance Weight = (DownWeight + UpWeight)/2

When measuring UpWeight and DownWeight the touch weights are placed on the key centered on a point 13mm in from the front vertical edge of the key.   When the balance weight is placed on the front of the key it is balanced and motionless as if it were a balanced scale.

Additional weight must be added to the balance weight to overcome friction and start the key moving down (DownWt) and weight subtracted from the balance weight to start the key moving up (UpWt).

Front Weight– The radius weight of the keystick pivoted on its balance point, taken at the front of the key.  It represents the downward static balancing force at the front of the key.

Front weight is found by placing the key on a wedge pivot so that the balance hole is centered across the edge of the wedge.  The front of the key rests on a roller bearing which is on the pan of a digital scale.

The key is oriented in a horizontal attitude similar to that when the key is at rest in the assembled action.  The roller bearing rests on a vertical axis through a point on the surface of the key 13mm in from the front vertical edge of the key (see Photo I).

Wippen Weight– The radius weight of the wippen pivoted on the wippen center, where the capstan contacts the wippen heel. The wippen heel rests on the roller at the capstan contact point.

The wippen flange rests on the felt wedge so that the wippen center is aligned with the vertical axis through the center of the roller.  If necessary the flange may be wedged with a sliver of wood to prevent the flange from rotating (see Photo 2).

Strike Weight– The hammer weight plus the radius weight of the hammer shank, pivoted at the hammer flange, taken at Strike Line Radius.  The strike line of the hammer rests on the felt wedge block and the end of the tipped up flange rests on the roller so that the flange center aligns with a vertical axis through the center of the roller. The height of the roller is adjusted so that the shank rests horizontally. Playing cards can be helpful as shims (see Photo 3).

Key Ratio– The ratio of down- wards force at the capstan to the corresponding upward force at the front of the key.  The key is set on the jig as for weighing front weight.  An amount of weight is placed on the front of the key to make the front weight at least 70 grams.

This weight holds down the front of the key. The scale is then tared to zero. (Digital scales have a tare button which makes the scale read zero, regardless of what weight is on the pan.)

Two 50-gram weights are placed on either side of the capstan so that there combined center of gravity is at the capstan/heel contact point.  The scale will then read how the 100 grams translates to the front of the key.  For instance, if the scale reading were -57.0 the key ratio would be 0.57 (see Photo 4).

Wippen Balance Weight– The upward static force at the front of the key from the leveraged weight of the wippen. Found by calculating:

WipBW = KeyRatio x WipWt

Top Action Balance Weight– The total upward static force at the front of the key resulting from the leveraged weight of the wippen, hammer, and shank.

Found as:

TopBW = BW + FrontWt

Strike Balance Weight– The upward static force at the front of the key from the leveraged weight of the hammer and shank.

Found by calculating:

StrikeBW = TopBW- WipBW

Strike Ratio – The amount of weight to balance one gram of strike weight at the front of the key.
Found as:

Strike Ratio = StrikeBW/StrikeWt


The New Touchweight Metrology bridges from the old Metrology of DownWeight and UpWeight through the Balance Weight, thereby maintaining the connection to traditional touchweight parameters.

The array of information provided by the New Touchweight Metrology gives a wealth of information that has heretofore remained hidden from us.  Of particular utility is the ability to measure hammer weight “on the shank” and the calculation of Strike Ratio.

The New Touchweight Metrology provides a useful and relevant framework for a more complete understanding of the balance of piano action mechanisms.

The weights and measures described above only partially describe the units and methods of the New Touchweight Metrology.  Other units and methods will be described in future articles.

In my next article I will show the results of studies using the New Touchweight Metrology and discuss the correlation between strike ratio and leverage which leads to the ability to rate the “dynamic” feel of piano actions using methodology of
the New Touchweight Metrology.


1. To the best of my knowledge, the Balance Weight value was first described by Don Galt, RPT, in “Resistance in Piano Action,” in the April, 1969 issue of the Piano Technicians Journal.  He called it Weight Resistance.  In the October, 1990 Journal is published a method for balancing keys to a specified Balance
Weight, by David C. Stanwood, RPT.

2. For this work, a scale needs to have 150-gram capacity and resolution accuracy of 0.1 gram. The roller bearing shown is an “idler bearing,” which can be purchased from small parts component suppliers. In a pinch, an edge-trimming router bit can be used.

3. In all cases it is only necessary to carry the decimal to the nearest tenth except for the “key ratio,” which is carried to the nearest hundredth.