Pianotech

David,  I agree, counter-clockwise while playing the note, measuring the amount of torque being applied at the point when the pin actually slips and the unison goes of of tune.  That's the measure of how much effective resistance the pin has against the pull of the string.  A Steinway factory guy told me years ago the acceptable torque is between 60 to 100 inch pounds.  In my experience most pianos I deal with out in the field are generally much lower than that, maybe 40 to 50 inch pounds, and time of year will affect your reading.

I read somewhere recently, I think a back issue of the Journal that the proper way to measure torque measure the torque going both flat and going sharp and subtract the two values, sort of like measuring downweight and upweight to find the friction and balance weight.  I don't remember the specifics and I don't know the value of going to that extent.  I think just measuring the torque necessary to get the pin to slip tells you all you need to know.

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John Gunderson RPT
Neptune City NJ
(732) 740-6674
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David,
Torque is measured with no string attached.

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Roger Gable RPT
Gable Piano
Everett WA
(425) 252-5000
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Original Message:
Sent: 08-16-2022 08:38
From: John Gunderson
Subject: Measuring tuning pin torque

David,  I agree, counter-clockwise while playing the note, measuring the amount of torque being applied at the point when the pin actually slips and the unison goes of of tune.  That's the measure of how much effective resistance the pin has against the pull of the string.  A Steinway factory guy told me years ago the acceptable torque is between 60 to 100 inch pounds.  In my experience most pianos I deal with out in the field are generally much lower than that, maybe 40 to 50 inch pounds, and time of year will affect your reading.

I read somewhere recently, I think a back issue of the Journal that the proper way to measure torque measure the torque going both flat and going sharp and subtract the two values, sort of like measuring downweight and upweight to find the friction and balance weight.  I don't remember the specifics and I don't know the value of going to that extent.  I think just measuring the torque necessary to get the pin to slip tells you all you need to know.

------------------------------
John Gunderson RPT
Neptune City NJ
(732) 740-6674
------------------------------

Roger and John - you are both correct. Theoretically, averaging torque in the the sharp and flat directions should give you the same torque value as the pin would if it were not strung.

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Terry Farrell
Farrell Piano Service, Inc.
Brandon, Florida
terry@farrellpiano.com
813-684-3505
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Original Message:
Sent: 08-17-2022 15:57
From: Roger Gable
Subject: Measuring tuning pin torque

David,
Torque is measured with no string attached.

------------------------------
Roger Gable RPT
Gable Piano
Everett WA
(425) 252-5000
------------------------------


Original Message:
Sent: 08-16-2022 08:38
From: John Gunderson
Subject: Measuring tuning pin torque

David,  I agree, counter-clockwise while playing the note, measuring the amount of torque being applied at the point when the pin actually slips and the unison goes of of tune.  That's the measure of how much effective resistance the pin has against the pull of the string.  A Steinway factory guy told me years ago the acceptable torque is between 60 to 100 inch pounds.  In my experience most pianos I deal with out in the field are generally much lower than that, maybe 40 to 50 inch pounds, and time of year will affect your reading.

I read somewhere recently, I think a back issue of the Journal that the proper way to measure torque measure the torque going both flat and going sharp and subtract the two values, sort of like measuring downweight and upweight to find the friction and balance weight.  I don't remember the specifics and I don't know the value of going to that extent.  I think just measuring the torque necessary to get the pin to slip tells you all you need to know.

------------------------------
John Gunderson RPT
Neptune City NJ
(732) 740-6674