[pianotech] Square grand rebuilding/repair

Joseph Garrett joegarrett at earthlink.net
Mon May 21 10:03:58 MDT 2012


Jim said: 
"/Joe said:
 
<I'm curious, since 425cps would only apply to something made before 
1875 and even then, would have to have solid reasoning to go that route/.
 
Its a Miller square which appears to be late 1860,s.
 
My reasoning was structural. In analyzing the string scale, I weighed 
the bass spiral wound wires to come up with existing tensions which @ 
435 hz ended up 180-200 lbs monochords, 250-275 lb/unison bichords. The 
pinning of the base bridge was so close together that the bass cap and 
root completely blew up...the poor cap never had a prayer.
 
In addition to that, there was a scary difference between the speaking 
lengths measured under tension and with tension zero'd out at some 
locations on the plate.
 
The pin offsets on the Bass bridge were inconsistent and quite 
aggressive, so that probably contributed to bass bridge mess..I 
corrected the offsets, and used a Delignit cap there.
 
But, considering the following points:
 
-that I have been experimenting with significantly reduced bass tensions 
on small venue modern pianos with what I consider to be excellent 
results (small Paullelo cores maintaining high BP%). FYI excellent 
results meaning less noise and growl, and more perception of 
fundamental, even on small scales.
-/Joe said:
 
<I'm curious, since 425cps would only apply to something made before 
1875 and even then, would have to have solid reasoning to go that route/.
 
Its a Miller square which appears to be late 1860,s.
 
My reasoning was structural. In analyzing the string scale, I weighed 
the bass spiral wound wires to come up with existing tensions which @ 
435 hz ended up 180-200 lbs monochords, 250-275 lb/unison bichords. The 
pinning of the base bridge was so close together that the bass cap and 
root completely blew up...the poor cap never had a prayer.
 
In addition to that, there was a scary difference between the speaking 
lengths measured under tension and with tension zero'd out at some 
locations on the plate.
 
The pin offsets on the Bass bridge were inconsistent and quite 
aggressive, so that probably contributed to bass bridge mess..I 
corrected the offsets, and used a Delignit cap there.
 
But, considering the following points:
 
-that I have been experimenting with significantly reduced bass tensions 
on small venue modern pianos with what I consider to be excellent 
results (small Paullelo cores maintaining high BP%). FYI excellent 
results meaning less noise and growl, and more perception of 
fundamental, even on small scales.
- the instrument is and was a parlor instrument, meaning power ( a 
relative term) is not desirable
- the client is not an accomplished pianist and does not play with other 
instrumentalists
 
I looked at the above structural indications, which I consider to be 
warning signs, and decided to hedge my bets as well as continue my low 
tension experiments. So I dropped the tensions some as well, though kept 
BP% respectably elevated)
 
Call me a masher if you like...sweet music to my ears...
 
Jim
 
I looked at the above structural indications, which I consider to be 
warning signs, and decided to hedge my bets as well as continue my low 
tension experiments. So I dropped the tensions some as well, though kept 
BP% respectably elevated)
 
Call me a masher if you like...sweet music to my ears...
 
Jim,
No "masher" here.<G> All are valid reasons to drop the tensions/pitch. I am
curious,...when you said: "the owner is not an accomplished pianist and
does not play with other instrumentalists." Hmmm? Does that mean that you
did NOT change the scale, but are simply tuning the thing to 425cps? That
is NOT the way I would recommend. If another tuner got involved and didn't
know all of the situation...decided to just tune that sucker at 440cps!
Yikes! The Scale needs to be changed, so that the instrument can be tuned
to 440cps, w/o causing undo stress on the weak components of the
instrument, imo.
That's my take on that.
Joe


Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I



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