low drop screw symptom

[Bob Hull]

Thanks, David.

The articles you may be thinking about were by Bob
Hoff, Action Elevations, June - September of 2000.  I
keep rereading them. 
I may check with Wally Brooks next time because I
don't think the Renner kit had any other choices that
had a larger roller and yet still had the other
necessary dimensions.

Cheerios,

Bob Hull

--- David Love <davidlovepianos@comcast.net> wrote:

> There was an excellent article in the journal a few
> years back on action
> elevations.  Can't even remember who wrote it now,
> but it might be worth
> reading at this point.  Someone with a better memory
> for these things
> will offer the author and issue I'm sure.  My
> general approach in these
> situations is to kind of start over and try various
> combinations of
> parts to see what gives me the best combination of
> regulation and
> leverage.  I try and at least get the convergence
> line from the balance
> rail to the wippen center on target with the
> capstan/wippen cushion
> contact point on the line when the key is halfway
> through it's travel.
> If you are using the wippen with the various cushion
> heights, you can
> play around until you get the one that works.  You
> can alter the spread
> as needed to get jack alignment with the knuckle
> and, sometimes,
> clearance between the hammer flange rail and the
> balancier.  I don't
> remember the configuration on a Weber that well
> without looking at one.
> If you are replacing shanks and can't find the right
> knuckle center
> dimension from Renner, check Abel shanks from Brooks
> Limited.  He has
> some configurations that Renner doesn't.  At this
> point, I think you
> just have to play around with samples.  Double check
> the bore distance
> to be sure that you are using a correctly bored
> hammer for your trials.
> 
>   
> 
> David Love
> davidlovepianos@comcast.net 
> 
> -----Original Message-----
> From: pianotech-bounces@ptg.org
> [mailto:pianotech-bounces@ptg.org] On
> Behalf Of Bob Hull
> Sent: Saturday, March 19, 2005 2:57 PM
> To: Pianotech
> Subject: RE: low drop screw symptom
> 
> David, 
> 
> Your comments are appreciated.  Here's my answer to
> your questions. 
> 
> --- David Love <davidlovepianos@comcast.net> wrote:
> > What kind of piano is this?
> 
> It is a  5'6" Weber which was rebuilt by someone
> else
> only 6 years ago but the pinblock was very poorly
> fit,
> the wippens were not replaced and cheap parts were
> poorly used. Now the wippens have failed (silk cord
> type)so we decided to start over and hopefully do
> things better.  
>  
> > If you have to lower the drop screw it may
> indicate
> > that the bore
> > distance on the hammers is too long.  Lowering the
> > let-off button is
> > usually accompanied by the lowering of the drop
> > screw and vice versa.
> 
> Andre said something about capstans having to be
> lowered and this is true, I am having to lower the
> capstans on the samples to set the hammer blow dist.
> 
> > The shank relationship to the knuckle can be
> altered
> > by changing the
> > spread, shimming out the whippen flanges or the
> > flange rail.  You will
> > have to determine the appropriate spread by trial
> > and error probably.  
> > 
> > The harder feel at let-off of the new wippen may
> be
> > because the surface
> > area of the top of the jack is greater on the new
> > one than the old one.
> > What condition are the knuckles in?  You may want
> to
> > consider changing
> > the knuckles if you are not changing the shanks.  
> 
> I am replacing the shanks but now I thinking about
> trying a different shank with a bigger knuckle if I
> can find the same dimension from the center pin.  I
> hate not having the original parts to reference.
> 
> > I would measure and calculate just how much you
> need
> > to lower the plate
> > to get the bearing you want and on which side you
> > have the problem.
> > Also, measure the crown.  If you are lowering the
> > plate onto a board
> > which is already flat or worse...  Lowering the
> > plate at the outside
> > perimeter is not likely to change the hammer bore
> > dimension.  Lowering
> > the plate at the block might, it depends on how
> much
> > you are lowering
> > it.  Are you installing a new pinblock?
> 
> I have already put in a new pinblock.  The board was
> repaired and coated with System 3 epoxy.
> I lowered the plate as much as I dared, just enough
> to
> get some downbearing but not push the board to hard
> because of its age.  I did have to lower it also at
> the block because the thread would contact the back
> of
> the bridge before the front as it came from the
> agraffe.     
> 
> > David Love
> > davidlovepianos@comcast.net 
> > 
> > -----Original Message-----
> > From: pianotech-bounces@ptg.org
> > [mailto:pianotech-bounces@ptg.org] On
> > Behalf Of Bob Hull
> > Sent: Saturday, March 19, 2005 7:23 AM
> > To: pianotech@ptg.org
> > Subject: low drop screw symptom
> > 
> > Hello List, 
> > 
> > On a rebuild for a small but good quality grand I
> am
> > replacing all of the action parts and having some
> > doubts about the action configuration.   As I
> > regulate samples the drop screw has to be lowered
> > almost as far as it will go.  
> > 
> > Another relationship that appears to be off is the
> > jack to hammershank relationship which is not
> > perpendicular but rather it is more toward the B-
> > side
> > (Bob Hoff terminology).  How can I change this?
> > 
> > The new (Renner) wippen with the closest match to
> > the
> > old wippen is the one with the added heel.  The
> old
> > jack tender/toe seemed to interface better with
> the
> > tilted let off rail than the new wippen does.  The
> > new
> > one gives a harder feeling ledge before let off. 
> > I don't like the way that feels.  
> > 
> > I  realize that more information may be necessary
> > and
> > I can supply it if asked.  One other thing I will
> > add
> > is that I had to lower the plate/string plane as
> > much
> > as I dared to get some downbearing.  I am
> adjusting
> > the hammer bore because of this.  
> > 
> > So to restate my question:  What is indicated
> about
> > an
> > action geometry when drop screws must be lowered
> so
> > far in order to attain suitable drop?  
> > I would appreciate your comments.
> > 
> > Bob Hull
> > 
> > 
> > 
> > 
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> 
=== message truncated ===



		
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