[pianotech] finding the strike line

[Delwin D Fandrich]

| -----Original Message-----
| From: pianotech-bounces at ptg.org 
| [mailto:pianotech-bounces at ptg.org] On Behalf Of David Love
| Sent: February 09, 2009 10:01 AM
| To: pianotech at ptg.org
| Subject: Re: [pianotech] finding the strike line
| 
| Why is that?  I noticed that you moved the agraffe line on 
| the Walters Grands that you developed with transition bridges.  
| 
| David Love
| www.davidlovepianos.com

Yes, I did. But that was on a new design and a new plate pattern. It seemed
prudent to at least start the piano out with the hammer strike point ratio (SPR)
I deemed "proper." When laying out a new plate design--or modifying an existing
production plate pattern--there is no reason not to do it right.

It's hard to say, however, just what SPR philosophy was being followed in many
piano designs (some of which are still in production today). There may have been
one at some early date but then the scaling was changed forty-seven years later
by someone who did not have a grasp of such subtleties with the result that as
the piano exists today there is no consistent SPR being followed. Or the scaling
was changed but no one bothered to change the agrafe line. Or the V-bar shifted
a time or two as the plate pattern was being repaired. Or the cope and drag
mated up out of alignment for a few (or a few thousand) castings. 

The bottom line is that, as a rebuilder, I'm pretty much stuck with what I get.
Unless, of course, I want to plug the original agrafe holes and redrill and tap.
Somehow it has never seemed worth the effort. Does some deviation from that
"proper" SPR make a tonal difference? Yes, but it may be a difference that is
only measurable using relatively sophisticated equipment and not one that is
readily audible. 

With existing pianos the proper use of a transition bridge--along with good
scaling--will reduce the timbrel variations due to deviations from the "proper"
SPR across the bass/tenor break to such an extent that they can usually be
voiced out without too much trouble. At least this has been the case with the
type of soundboard construction and the overall scaling philosophy I've been
using for the past thirty-five years or so.

ddf