[pianotech] re; Action Ratio Measuring

[Delwin D Fandrich]

Assuming a rather poorly set up key to wippen relationship and assuming a
very short key (i.e., one typical of a 150 cm grand) the sliding motion will
be about 0.2 mm (or about 0.008"). Most actions-properly set up and with
longer keys-will have less than this. 

 

There is so little sliding motion between the capstans and the wippen that
the capstans typically corrode and discolor. If there was any appreciable
sliding motion they would polish themselves. 

 

ddf

 

Delwin D Fandrich

Piano Design & Fabrication

6939 Foothill Court SW, Olympia, Washington 98512 USA

Phone  360.515.0119 - Cell  360.388.6525

del at fandrichpiano.com  <mailto:del at fandrichpiano.com> - ddfandrich at gmail.com

 

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Dale Erwin
Sent: Saturday, September 22, 2012 7:05 PM
To: joegarrett at earthlink.net; pianotech at ptg.org
Subject: Re: [pianotech] re; Action Ratio Measuring

 

Hi Joe

Wether the  casptan is straight or angled, watching it move thru its motion
changes its contact point with the wippen heel. Not by sliding but by
rotating. Its not much and I'll choose not to split hairs about it. Ok?

Dale Erwin R.P.T.
Erwin's Piano Restoration Inc.
Mason & Hamlin/Steinway/U.S. pianos
www.Erwinspiano.com
Phone: 209-577-8397

 
  

 

-----Original Message-----
From: Joseph Garrett <joegarrett at earthlink.net>
To: pianotech <pianotech at ptg.org>
Sent: Sat, Sep 22, 2012 6:51 pm
Subject: [pianotech] re; Action Ratio Measuring

Dale said: "All actions are subject the accelerating action phenomena to
changing ratios thru the complete range of motion as the capstans is moving
further from the wip center pin and the increasing leverage efficiency in
the wip."
 
Dale,
I can't agree. The capstan does not move but a miniscule "...further from
the wip center pin...". Del brought this to my attention during a Key class
I was giving. I agree with Del, ...that there is little movement of the
capstan along the wippen foot felt! They are so close to linear to each
other that the differences of their arcs is pretty much negligible imo.<G>
Joe 
 
 
Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I
 
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