Stability concerns

[Roger Jolly]

Greetings Don,
               I guess I'm the bridge tapper.  The piano in question is a
new Yamaha C2.  A suprise to me that the pitch was that close.
  An insecure string at the bridge will wander at will. How ever the coil
has some assistance from the friction of the forward termination system,
and in my humble opinion is less important. Unless the coils have visible
gaps, I do not routinely tighten coils. But I will ALWAYS secure strings to
bridge, plate, and level strings, on all of our new grands. 
 On the piano in question, from the bridge work, it dropped 50 to 100cents
in the upper treble. My concern is not just tuning stability, but
efficientcy and false beat removal prior to voicing.
 After some thought re coils, the impact device that you use to tighten
them, can deflect the wire that is coming away from the pin, any slight
movement in this area will result in pitch changes, the friction is the
real poser if you are trying to do some comparative analysis. We have all
seen pianos out there with bad coils that have reasonable tuning
stability???????  However with poor bridge seating, stability and clean
unisons is imposible.
 Just adding a little more confusion.
Roger.




At 11:53 PM 4/19/98 -0700, you wrote:
>Hi all,
>
>I have had a chance to do some *interesting* comparisons recently.
>
>The contest:
>
>Tightening tuning pin coils VS tapping strings down on the bridge.
>
>Results so far:
>
>Attempt #1 coils then bridge
>
>tuning pins pitch drop between 21-118 cents
>setting strings pitch drop between 18-69 cents.
>
>I hope to try the reverse order very soon on an instrument.
>
>It seems so far that coil setting is *more* important than setting the
>strings on the bridge--but that setting the strings lowers the pitch more
>*evenly*.
>
>I have done the coils on one instrument *after* another tech had set the
>strings on the bridge. Piano was between 3 and 18 cents flat before coil
>tightening. After the proceedure pitch was 37 to 133 cents flat!
>
>
>Regards,
>Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T.
>"Tuner for the Centre of the Arts"
>drose@dlcwest.com
>Web Site: http://www.dlcwest.com/~drose/
>3004 Grant Rd.
>REGINA, SK
>S4S 5G7
>306-352-3620 or 1-888-29t-uner
>
>
Roger Jolly
Balwin Yamaha Piano Centres.
Saskatoon/Regina.
Canada.