[pianotech] Managing agraffes was Increasing bridge height

[Jude Reveley/Absolute Piano]

Thank you for a well reasoned response, Frank. (BTW great cap/whip post-I'm 
still mulling).

Now, it is not uncommon to arrive at the proper agraffe angle somewhere at 
or before the border torque specification of "finger tight." My procedure 
has been to bring it around another 180 degrees for all the reasons 
mentioned in this thread, and I willingly admit this will occasionally twist 
me out of my own comfort zone for fear that I might be stressing the agraffe 
at the threads leading to all kinds of imagined catastrophies, present or 
future. I've used washers and counterbores but am not wholely satisfied with 
those techniques because of their inherent disadvantages, namely time 
consumption and flattening the shoulder at the base; so I'm looking for 
options.

I wouldn't mind a counterbore that would maintain a shoulder. Suppliers? 
Listening? Jurgen? I could especially use it for those fun vintage 
Becksteins.

So based on this survey, I suppose I'll stick with tight; but I'm still 
trying to get a sense of when is too tight. I figure if I had a spec for 
this limit, I could take some measurements and develop the feel. Then I can 
get on with it, as Ron suggested.

As to new agraffes vs. old, for me it comes down to weighing the 
cost/benefit.  Polishing old ones remains more expensive than buying new 
ones and spending a little extra time refining the holes. I save the old 
ones for when this may not be the case. I borrowed my method from Paul-Flitz 
on a quill-like buffer in a dremel or foredom.

Paul: Hoping you still read every post with "agraffe" in the tiltle...what 
are you using for a buffer? I find are q-tips too big. I made some from 
hammer felt scraps but am interested trying something store bought?

Thanks,

Jude Reveley, RPT
Absolute Piano Restoration, LLC
Lowell, Massachusetts
(978) 323-4545

----- Original Message ----- 
From: <pianoguru at cox.net>
To: <pianotech at ptg.org>
Cc: "Jude Reveley/Absolute Piano" <juderev at verizon.net>
Sent: Thursday, March 26, 2009 8:33 AM
Subject: Re: [pianotech] Managing agraffes was Increasing bridge height


> ---- Jude Reveley/Absolute Piano <juderev at verizon.net> wrote:
>> Did you interpret the use of threadlock to be in the agraffe hole or at 
>> the
>> threads. I can imagine threadlock around the agraffe threads robbing only 
>> as
>> much energy as a tuning pin bushing. How is this related to a rigid
>> terminus?
>
> With or without thread lock, if the agraffe is loose, ie. lacking solid 
> contact around the head of the stud in the counterbore, this constitutes 
> something less than a rigid terminus.  To suggested the possibility of 
> vibration of the agraffe, in itself, constitutes lack of rigidity.
>
> To suggest the use of Thread Lock is concede that potential vibration is a 
> legitimate concern.  To suggest a softer fomulation of Thread Lock in the 
> interest of serviceability is to defeat the argument for its use in the 
> first place.
>
> Putting aside the concerns for vibration and rigidity, do you suppose it 
> would be an acceptable practice to finger tighten all agraffes, and back 
> them off from finger-tough, to align each agraffe to an alignment 
> perpendicular to its speaking length(s)?  I've seen this in new piano 
> production.  It's not pretty.  All I'm saying is that nothing short of 
> tightening the agraffes beyond finger-tight, will insure a rigid terminus 
> and proper alignment.
>
> Frank Emerson
>
>
>