Loading the tuning pin

[paulrevenkojones at aol.com]

 Ron:

I think my point is simpler than it may have been taken as. The "feel" of stablized pin "load" is a combination, in any measure, of all the twist, friction, torque, and bearing conditions. Granted that there are primary forces, and that friction in the front system is nominal, it still speaks to the "feel" of pin setting, and string stability settling. 

Try this. After you have set a pin and gotten it as "stable" as you can, if you take a brass drift and tap the counterbearing segment up from below just past the counterbearing bar, and down from the top just in front of the capo or agraffe, measure the pitch change and get a sense of the embedded and residual friction maintaining the tension of the the tuned string. It's not insignificant. It may not be terribly significant either, but there it is. I think Jim Ellis has a lot to say on this, too, and I would do well to go back and review his material before getting too ethereal. :-)

Paul


 


 

-----Original Message-----
From: Ron Nossaman <rnossaman at cox.net>
To: Pianotech List <pianotech at ptg.org>
Sent: Sat, 30 Aug 2008 11:01 pm
Subject: Re: Loading the tuning pin









?

> ...along with all of the friction points in the string system, as well, 
> particularly the front segments. With string tension, the pin is twisted 
> axially and in a diminishing amount of torque to the bottom of the pin 
> depending on the friction of the system in the block. The friction and 
> stability of the friction system of the counterbearing felt, 
> counterbearing contact, agraffe or capo will be additive to the 
> perceived "loading". Ron is exactly right that there is no way to tell 
> what twist component remains in the pin because of all of the above 
> complications. I think I'm interpreting what you're saying correctly, Ron.?

> 
> Paul?
?

Essentially, but conditionally, as you likely suspected. All 
the front friction points cancel with the relationship between 
what you do and what you hear, when you get an instant aural 
response from pin movement. This is the odds on norm, so front 
friction points can be mostly eliminated as a universal 
absolution of responsibility for most tuning stability 
problems. Those aberrant instances where pitch change doesn't 
correspond to pin movement because of the above mentioned 
friction issues belong in an entirely different category of 
dysfunction from typical tuning cause and effect issues, and 
aren't therefor available as a mainstream "not my fault" 
dodge. For the most part, we do, we hear, and we sign off on 
the result. The "not my fault" from front friction thing is 
entirely real in some instances, and a monumental pain in the 
ass when encountered, but it isn't especially extant in most 
instances, though typically invoked first as an excuse.?
?

That leaves the more prosaic balancing of pin back torque to 
string tangential tension effect as the primary issue in 
producing a stable tuning - reluctantly skipping over the back 
scale.?
?

It's really pretty simple, eventually.?

<G>?

Ron N?



 

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