overcentering justified?

[Bob Hull]

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Roger Jolly <roger.j@sasktel.net> wrote:


6. Finally on Steinway's. Is the wippen rail slightly rotated? I have 
shimmed quite a few sets of flanges to correct this, to restore the magic 
line, and action spread.  

PS I don't know if hammer rake has been mentioned, but over centering is a 
no,no, with a new set of hammers period. Slight under centering, you can 
always file or play in, to fit. 

Regards Roger 




Thanks, Roger for these comments.  I wanted to let you know and also, David and Ed, what I observed today when I was back at this piano.  
These strings do rise toward the bridge.  Maybe about 3 degrees of rise - but I'm not sure if I measured that accurately.  However, I know that the hammer shank should match that amount of rise upon contact with the string so I put a little line level on the shank.

On some of the old hammers the wear is significant so I had to guess about how much more hammer there would have been when it was new.  The holes I have already bored, unfortunately, are probably making the hammer "too long" and undercentering.  The bore distance I used was the result of doing the simple math: subtracting the heighth of the hammer flange center pin from the string height ( and not accounting for a rising string). 

I don't think that there is enough said about that kind of potential error.  

Tomorrow, I want to plug a couple of these long bored hammers and rebore them at the distance of 48 mm like the old ones.(Instead of the 2 inch bore)  Then, I will try those on the piano before I do the rest.  Is this a smart approach?  I tried regulating (aftertouch priority method) the long bored hammers  and their new shanks but to get a note to play really well, a real short blow was required, like 41 mm.

The plugs will need to be end grain on the side, true?  What is the best way to make those?  A hardwood dowel would have incorrect grain orientation I think.  

Can you visually detect rotation in a wippen rail? 


Gratefully,

Bob Hull

 

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