This is a multi-part message in MIME format.
---------------------- multipart/related attachment
------=_NextPart_001_0016_01C32165.82285280
Re: No Power Yamaha revisited (accurate bedding adjustI wrote of this =
before, what do you think of my method, Ron. I mean, who needs a dial =
indicator when you have a business card?
"David, and all, your method is quite a bit like mine. Rather than buy a =
Jaras tool, you can do the same thing without it.=20
What you're looking for is the fact that when the balance rail =
contacts the keybed the keys will begin to raise. I take a business card =
and cut it so that it's just a little taller than the keybed-keytop =
distance. When you put it under the keytops, it will form a slight =
curve. Then, I put the balance rail bedding tool on the glide and, as =
you describe, push down on it. If it's not bedded you can see the card =
flex quite dramatically. Then you can turn the glide bolt in, and as =
soon as the glide bolt contacts, the card will start to straighten out. =
Work from the center out, when you're done, you can do the "lift and =
tap" final check.=20
This get's you real close, real fast.=20
Hey, a card's a lot cheaper than any other tool I know.=20
Kevin."
"Bobbing [adjacent] hammers" is a clear indication that not all glide =
bolts were accurately adjusted.
I remember back about 1990 when a Steinway tech visited Sydney for a =
three day technical workshop. Two grands were to be regulated by a small =
group of invited technicians.
On the first day the usual paper shim under the bolts, lifting and =
tapping procedure was demonstrated by the Steinway technician, to show =
the locals just how it was done. I wasn't impressed since we had for =
some years been using our own dial-indicator procedure (which is =
accurate and quick - a while back the PTG published one of my documents =
detailing this procedure in the Journal).
On the second day of the seminar I bought in my dial indicator and =
wooden mounting block, to demonstrate our procedure. Sure enough, the =
glide bolt adjustment was 'all over the shop'. The visiting tech seemed =
unimpressed with our alternative procedure. It never ceases to amaze me =
how many folks stick with an inferior procedure just because its 'the =
way we've always done it'.
Anyhow, for those who may be interested in our procedure, I will take =
you through the process.
A dial indicator is mounted in a small wooden block with a single hole =
sized to create a slight interference fit with the rear plunger cover of =
the dial indicator (see diagram below).
The mounted dial indicator is used to set exactly the adjustment of =
each glide bolt, so that each just makes contact with the key bed. After =
the precise contact position has been established, each bolt is =
re-adjusted down a further small amount to ensure that the key frame =
doesn't lift the glide bolts clear of the key bed during variable =
weather conditions.
The procedure we use is as follows;
* All glide bolts are adjusted up to clear the key bed while the =
touch blocks are fitted to the piano and tightened. If an action has mid =
section glide bolts (eg. Yamaha) you will need to remove a key over each =
one to enable adjustment access with the action in the piano. These also =
are initially adjusted to clear the key bed.
* The dial indicator is positioned right next to each glide bolt =
in turn, with the wooden block resting on top of the balance pins while =
the dial indicator plunger is depressed by the underside of the pin =
block (and showing a measurement which is mentally noted). The adjacent =
glide bolt is adjusted down until the dial indicator moves just 1 thou' =
or 0.025 mm. This procedure is repeated for all glide bolts until all =
are just contacting the key bed.
* Now repeat the adjustment procedure again, only this time adjust =
all glide bolts down a further 5 thou' or 0.125 mm.
That's it!
The reason behind adjusting the glide bolts to a just-contacting =
setting, before finally pre-loading the balance rail, is that the =
initial 1 thou' or 0.025 mm adjustment will not cause any positional =
change of the balance rail which might interfere with the initial =
setting of the other glide bolts. The end result is absolutely accurate =
and, provided that the front and rear contact surfaces of the key frame =
to key bed are accurate, it will be quiet and there will be no 'bobbing' =
hammers.
Dial indicators are generally available at any good engineers supply. =
The one illustrated above was lifted from the Cutting Tool Mall website =
at;
http://www.cuttingtoolmall.com/catalog/standard.cfm?FamilyID=3D900100
Cutting Tool Mall is in New York state, they sell on-line, and the =
prices look OK. Furthermore, when used with a magnetic stand, the dial =
indicator can be used between the plate and the bridge as the definitive =
tool for adjusting the set bolts. We set-up our pianos with the set =
bolts just contacting the plate in its resting position. There are many =
uses for a dial indicator in piano work.
On my return trip from the 2001 Reno convention I called on Richard =
Davenport and toured his LA workshop. Richard had independently come up =
with the same idea of using a dial indicator for setting the glide =
bolts. So all roads do lead to Rome.
Best,
Ron O.
--=20
_______________________
OVERS PIANOS - SYDNEY
Grand Piano Manufacturers
Web: http://overspianos.com.au
mailto:info@overspianos.com.au
_______________________
------=_NextPart_001_0016_01C32165.82285280
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/fb/1b/03/c7/attachment.htm
------=_NextPart_001_0016_01C32165.82285280--
---------------------- multipart/related attachment
A non-text attachment was scrubbed...
Name: not available
Type: image/jpeg
Size: 17893 bytes
Desc: not available
Url : https://www.moypiano.com/ptg/pianotech.php/attachments/ff/b1/dd/50/attachment.jpe
---------------------- multipart/related attachment--
This PTG archive page provided courtesy of Moy Piano Service, LLC