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Re: Fw: Short Treble (sustain?)
----- Original Message -----=20
From: Overs Pianos=20
To: Pianotech=20
Sent: Wednesday, November 05, 2003 1:52 PM
Subject: Re: Fw: Short Treble (sustain?)
At 9:58 PM +0000 4/11/03, Michael Gamble wrote:
Why not see what response your observations get from Grotrian-Steinweg =
themselves?
Ron Overs replied:
The recapping job I mentioned was undertaken back in 1989. I have =
observed since then, many other instruments from the same manufacture =
with similarly inappropriate bridge pin spacing (often with the =
resultant elongated or completely collapsed bridge pin holes). =
Furthermore, with regard to the piano repair in question, the intention =
originally was to recap the treble bridge only. After re-cutting the =
notching and re-drilling the bass bridge in preparation for the oversize =
bridge pins, we found that the front and rear pins (in the bichord =
section) were running into each other towards the bottom of the bridge =
pins holes. To explain further, while driving the back scale pins they =
were running into the speaking length pins somewhere below the bridge =
cap.
I was absolutely less than impressed at the time. Since we had to turn =
around and recap the bass bridge and re-position the back row of pins to =
cure the problem. If a factory, which lays claim to making a quality =
piano, can't even get the bridge pin field laid out so that the pins =
don't run into each other below the bridge cap, I can't see the point in =
contacting them to tell them about it. After all, most messengers =
usually get shot, and what would a small time piano re-builder down in =
the colonies know about the problem anyhow?
Do you mean Model 220? Or should it be Model 225?
The Grotrian seven foot class of grand piano in the early '70's was a =
220. A 223 was released sometime after 1975 (my first year working with =
pianos).
I have a superb 225 on my rounds and have been corresponding with =
Grotrian on the subject of a 10 year service/regulation.
The 225 is a later piano again. Would you measure the bridge pin =
spacing, in the highest treble string section, between the outside =
unisons (centre to centre) next time you see it? I'd be interested to =
know if they are still building them the same way.
Ron O.
-------------------------------------------------------------------------=
-------
Hello Ron O. Yes. I will take my 1/64" depth rule (which I usually use =
for measuring string heights in Grands) and measure the top break bridge =
pin spacing. I next see this piano on Friday 28th. November to prepare =
it for a recital by Leon MacAulay.
Interestingly I just did its first 10yr. action regulation on it a =
couple of weeks ago and found the key dip was down to 9mm and the =
hammer-rise almost non-existent. When new, the hammer-rise was fast and =
furious!!! so I strengthened all the double-winged jack springs, put =
0.3mm paper punchings under every balance rail pin washer, then adjusted =
the set-off and let-offs. There had been complaints from Susan Tomes (in =
particular) of the "non-responsiveness" of this 225. We shall see. It =
has no spring assists as the playing weight was specified to be 50gms.
I am horrified to hear of your findings in that G-S 220 where the =
speaking bridge pins are touching the duplex bridge pins =
"subcutaneously"! I shall have to measure the bridge-width (distance =
between the front-back pins) as well I think, and mic. up the bridge =
pins if I can get at them with the micrometer. Then you can tell us your =
opinion on this newer beastie. :-)
Regards
Michael G (UK)
----- Original Message -----
From: Overs Pianos
To: Pianotech
Cc: Alf Reichardt
Sent: Monday, November 03, 2003 10:21 PM
Subject: Re: Short Treble (sustain?)
Del, Ron N. and all,
The string buzzing on the side of the agraffe slot is most certainly =
the problem. Earlier in my career I recapped the failed bridges on a =
Grotrian 220. Since the owner was travelling to Germany on business, =
when he visited the factory they sold him a replacement treble bridge =
cap. Unfortunately, the new bridge cap was afflicted with the same =
'disease' which was common to '70s era Grotrians (I have no idea if it =
remains a problem with their contemporary instruments). However, the =
bridge pin spacing was so close that there was virtually no free space =
between the string and the adjacent bridge pin. Consequently, there =
remain several notes on my client's Grotrian 220 which have string noise =
at the bridge pins (which varies in intensity according to the relative =
humidity at the time). A gentle side pressure on an offending bridge pin =
will stop the noise.
These Grotrian bridges from the '70s are prone to failure on account =
of the close bridge pin spacing. There is simply insufficient bridge =
wood around the pins to provide adequate support for the side thrust on =
the pins. On Grotrians from earlier periods they have used a wider =
bridge pin spacing and they do not have the same problem. Isn't it =
amazing how corporate knowledge often fails to be passed down from one =
generation to another? The 'Johnny come latelys' turn up with new =
thinking but fail give appropriate consideration to lessons learned long =
ago by an older generation of thinkers. I'm all for innovative =
technologies, but one should come to it after stepping off from the =
knowledge which has gone before.
Clearly, the idea of placing a damping material on a noisy string =
segment (wether it be new-age silicon as in the case of the Stuart =
agraffe, a piece of felt or a lump of fat from under the barbecue), its =
still is just a case of fixing the symptom instead of addressing the =
cause of the disease.
The bridge agraffe we have been discussing is a case in point. It =
simply wasn't thought through prior to execution. I concur with your =
views Ron N. and Del, with regard to widening the slots and using rolled =
pins as a solution. Less overall height would be a plus as well. As you =
and I have both mentioned previously Ron N., it would allow for the =
retention of a more sensible bridge height and stiffness.
Ron O.
----- Original Message -----
From: "Ron Nossaman" <RNossaman@cox.net>
To: "Pianotech" <pianotech@ptg.org>
Sent: November 01, 2003 8:23 PM
Subject: Re: Short Treble (sustain?)
I suspect the problem is with the string buzzing against the side of =
the
slot.
Del
Perhaps, though I have a hard time imagining much vibration =
excursion in
that short segment. At that, how difficult or more expensive is a =
wider
slot, as long as you're cutting one anyway? It's not like it will =
cost
anything important in rigidity. A grooved center rod would help =
too,
though
it would cost a bit more to produce.
Ron N
-------------
As do I. I did think it a possibility, though, as I worked with =
similar
devices at Baldwin. The easiest way to solve the problem (if it =
exists)
(and, other than putting some damping material between the leading
termination and the center deflector rod) is, as you suggest, to =
groove the
center rod. This could be rolled and, in quantity, is not as =
expensive as
you might think. In limited quantities, however, it might well be a =
factor.
This can be used to solve another problem as well -- the varying =
string
deflection angles as the wire size changes. I played around with =
several
groove depths, deeper in the low tenor and bass, more shallow in the
tenor/treble.
Del
--
OVERS PIANOS - SYDNEY
Grand Piano Manufacturers
_______________________
Web http://overspianos.com.au
mailto:info@overspianos.com.au
_______________________
--=20
OVERS PIANOS - SYDNEY
Grand Piano Manufacturers
_______________________
Web http://overspianos.com.au
mailto:info@overspianos.com.au
_______________________
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