[pianotech] Upright Action Geometry

[Gregor _]

Floyd,

I am not shure if I understand your question correctly. The first that comes into my mind: measured from which point? I guess you are asking for something that refers to what we call in German "Stielschräge". I.e.: bring the hammer to the string and measure the distance from the upper point of the shank to the string and measure the distance of the lower point of the shank to the string. The difference between these two measures should be the thickness of the shank, usually 6 mm. This Stielschräge depends on the hammer bore angle and the position of the shank in the hammerbutt.

Gregor

> From: fg at floydgadd.com
> To: pianotech at ptg.org
> Date: Mon, 18 May 2009 10:05:52 -0500
> Subject: [pianotech] Upright Action Geometry
> 
> List,
> 
> I'm assembling an vertical action model as described in the Journal several
> months ago.  I neglected to take one measurement when I was disassembling
> the piano from which I got my parts.  What should be the angle relationship
> between the hammershank and the string plane when the hammer is in its
> striking position?  I've found an article by Jack Krefting in the '82
> Journal that states that in a grand the two should be parallel.  Is this
> also true for the vertical action?  Does having the answer to this question
> represent a method for establishing bore distance in an action where the
> hammers are so badly worn that the original bore distance is uncertain?
> 
> Floyd Gadd
> Manitoba Chapter
> 

_________________________________________________________________
More than messages–check out the rest of the Windows Live™.
http://www.microsoft.com/windows/windowslive/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ptg.org/pipermail/pianotech.php/attachments/20090520/92f97892/attachment-0001.htm>