Jim -
Look at October - November 2006
Conversation between Ric Brekne (RicB) and Overs. I've never used Archive before. Got some help from Sean at Home Office. If you don't know how, I'll try to explain. Right now, the stress of it requires that I lie down for a while. Hope this helps you. It's very timely.
From Ron Overs <
sec@overspianos.com.au
>
Hi all,
At 10:48 AM +0100 10/11/06, RicB wrote:
>... I'd like to hear more about how you go about designing a change
>in the lever systems. I remember my brother Joe doing this to
>accommodate pianodisk systems... tho I dont think he was concerned
>directly with the lifting ratio... more a matter of making
>everything fit.
>Still.. this might be a nice addition to ones technical toolbox as it were....
At 5:01 AM -0600 10/11/06, Conrad Hoffsommer wrote:
>I second this. The difference in feel, usually expressed as
>"heavy"/"light", has been noted more lately by both students and
>faculty.
The lift ratio and the resistance of the pedal system are two
separate issues, regarding the performance of the sustain pedal. Most
manufacturers fit a return spring to the damper lift tray, the
sustain lever directly under the keybed, or both. The return spring
on the damper lift tray can create problems over the longer term,
since its not usually possible to position the spring directly over
the push rod. When the return spring is offset from the push rod, the
damper lift tray can develop a compression-set warp over a number of
decades. This is a long term problem which won't usually occur while
those who built the piano are alive. Eventually, once the builders
are lying quietly in a box on a hillside somewhere, some repair tech
in a workshop might be found whining about another case of poor
design staring them in the face, as they deal with a warped damper
lift tray.
I prefer not to fit a return spring on the damper lift tray for the
reasons above mentioned. For those damper systems where the push rod
is located via a bushed guide hole in the keybed, it is best to
convert these by drilling a larger clearance hole in the keybed and
fitting a push rod with a guide pin in each end. This will be
quieter, creating less friction and noise. Its a good policy to make
and fit a new pin-guided push rod when rebuilding pianos with the
older style bushed push rod.
As mentioned in my previous post, most pianists seem to prefer a
pedal/damper lift ratio of between 2.5 to 3.25 to 1. When making an
adjustment to the ratio, I prefer to set it between 2.5 to 3.0. But
for some pedal systems 3.25 is about as high a ratio as can be
achieved using a single lever under the keybed. So, in these cases
I'll go as low as 3.25 because the double lever design, as used in
the Grotrian 275 conversion image I posted yesterday, is a whole lot
more trouble.
I check an existing damper lift ratio by measuring the damper-head
lift, and measuring the damper pedal travel from the end of the lost
motion to full lift. The pedal travel is divided by the damper-head
lift to arrive at an overall ratio.
If I need to revise the ratio, the formula for calculating the lever
lengths is similar to the formula I use for calculating action
ratios. Each pair of lever lengths is divided one into the other,
with the three results being multiplied together to arrive at an
overall ratio.
The three lever lengths are the pedal pair, the lever under the
keybed pair, and the damper tray pair. Here's a graphic to show the
various lever lengths A - F.
The pedal/damper lift ratio is calculated using the following formula.
(A/B) X (C/D) X (E/F)
For many damper systems, the push rod will come through the keybed to
contact the damper tray almost directly under the damper wire flange.
In these instances you can disregard the lever lengths F and E,
giving them a value of 1. There will be some small variation in the
actual ratio due to variations in the lever angles from piano to
piano. However, the variation is too small to worry about in practice
with respect to the ratio, but the lever angles are critical with
regard to friction.
If the push rod is fitted with guide pins the angle of the push rod,
with respect to the damper tray and damper lever, won't be of much
consequence, since it will contribute very little friction. The
damper lever under the keybed is a different matter. I prefer to set
this lever so that it is horizontal at half damper lift. This
arrangement will minimise friction between the lever and the lyre
push rod. For our own 225 piano, we machine away the lower-half of
the damper lever thickness where it meets the push-rod capstan, and
lengthen the lyre push-rod so that the lever is horizontal at half
damper lift. This results in less friction and less likelihood of
squeaks developing between the lyre push-rod capstan and the lever
bearing-felt.
I hope you have found the above mini-doc to be useful, since this is
the first time I've written-up the procedure onto something more
substantial than a piece of scrap of paper around the workshop.
However, its been good for me to document the procedure.
For those of you who would like to know how I produced the graphic
and imported it into the Eudora programme, here is the procedure.
1) Draw the graphic using my old 2D CAD programme.
2) Capture a screen image of the drawing and save it to the desktop
as a TIFF file.
3) Open the TIFF file in Photoshop, resample, reduce in size and save
as a jpg file.
4) Drag the jpg file into the Eudora email document.
Ron O.
--
OVERS PIANOS - SYDNEY
Grand Piano Manufacturers
_______________________------------------------------
David Skolnik [RPT]
Hastings-on-Hudson NY
917-589-2625
------------------------------
Original Message:
Sent: 12-28-2020 14:45
From: Jon Page
Subject: A question for concert techs
It's probably in the archives.
------------------------------
Regards,
Jon Page
mailto:jonpage@comcast.net
http://www.pianocapecod.com
Original Message:
Sent: 12-28-2020 09:41
From: Jim Ialeggio
Subject: A question for concert techs
No...can you post?
------------------------------
Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 12-28-2020 09:25
From: Jon Page
Subject: A question for concert techs
Good points, also, do you have the notes and graphic Ron Overs made a few years ago about pedal leverage ratio?
------------------------------
Regards,
Jon Page
mailto:jonpage@comcast.net
http://www.pianocapecod.com
Original Message:
Sent: 12-28-2020 01:02
From: David Love
Subject: A question for concert techs
First, a precise regulation of the damper timing is required. Installing capstans on the damper tray helps there.
Second, take some resistance out of the pedal by removing the trap lever springs which are often unnecessary and replace any leaf springs on the tray with coil springs located near the pitman. All you really need is enough of a spring to push the tray down away from the damper levers.
Steinway sustain pedals, for example, are generally way too stiff, IMO, and make subtle half pedaling much more difficult.
Original Message:
Sent: 12/27/2020 9:56:00 AM
From: Jim Ialeggio
Subject: A question for concert techs
Concert techs out there...
I am wondering if there is a way to regulate the sustain pedal to allow the lightest lift...not even a lift of the dampers, just an un-weighting of them, repeatedly in flutter pedaling. Not the bass so much but tenor and 1st capo. Though maybe the trick would be to use the middle pedal on my vintage Chick 106, which lifts the wraps only...but I don't think so. have been wanting to make it easier to do this for a long time, working on Debussy and Schubert, at mp-ppp. I really would like to be able to do this better. However, I find the ankle control so tiny, the only way I can do it the way I want to, is to stare at the dampers while pedaling.
Any ideas on how I could set this up better mechanically? Do performers ever voice a desire to be able to do this better, or at all?
------------------------------
Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
------------------------------