tuning pin torque

[William R. Monroe]

Hi David,

I'd concur with what Terry writes re: an acceptable range.

You also ask how many measurements should be taken.  The short answer is it depends on how many pins you want to know the torque readings on.  You need to decide the frequency of readings based on your experience with the instrument.  

If I were doing it, and I felt very confident that the instrument is pretty consistent throughout in terms of torque based on feel when tuning, I might settle on a dozen readings or so.  However, that is rarely the case, in my experience.  Since this is a potential warranty issue, I might suggest contacting S&S and ask what they want.  

I guess one pitfall I'd want to be sure to avoid is not getting readings for those that are the worst offenders.  If you have time and interest, I'd suggest taking as many readings as you can, on up to all of them.  In the end, it's a decision you need to make, and one that you will have to live with.  Just make sure you do everything that needs to be done to give your clients a fair shake.

Best,
William R. Monroe


  There will certainly be some variation of opinion on what "acceptable" tuning pin torque might be, but maybe about 60 to 150 in.-lbs. (note: inch-pounds, not foot-pounds) will yield a reasonable-tuning piano. When you get up in the 200 in.-lb. range (like some new Baldwins, etc.) those pins are so tight that it is difficult to fine tune the piano. Likewise, as torque falls below 50 in.-lbs. or so, the pin might still hold pitch (at least for a while), but it is hard to control/tune because it is so loose. Many would pick the 80 - 120 in.-lb. tuning pin torque as being ideal.

  To measure torque accurately, it would be ideal to have the string off the pin. Simply move the pin both ways with a torque wrench and note the resistance to movement. If the string is on the pin, move it both ways - it will give a higher reading pulling the pitch up and lower reading when lowering the pitch - and average the two measurements together - that, theoretically, should yield the same torque value as having no string at all.
  ...........
  Terry Farrell
    ----- Original Message ----- 
     I have a new S&S "D" that I need to measure the pin torque and I've been looking in all the literature I have, searched the pianotech archives and I have found no information on what would be acceptable ft/lb readings. Also, should I have the wire at the proper tension or should I get a reading with the wire removed? 

    I'm ashamed to say that I have never performed pin torque evaluation before. For a proper evaluation should I take readings in every gauge of the scale?  I really have no idea what the proper procedure is to give a understandable evaluation for the factory to use to determine the component condition. 

    The "D" is a Roger Williams instrument that was built this year and pin tightness is minimal to the point of almost untunable. 

    Any help will be greatly appreciated. 

    David Chadwick
    Las Vegas
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