tuning pin torque

[Farrell]

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.

Hmmmm... how's the weather in Las Vagas this time of year? Looooowwwww humidity? What kind of environmental conditions is the piano being exposed to?

BTW: What is a "Roger Williams instrument"?

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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