[CAUT] S&S M Strike point

[Dale Erwin]

Hi Ed
  I recall this discussion before and I've given thought to this method. 
   Considering that it does appear that the hammers/shanks on ancient Steinways & others  seem to over center a bit, perhaps your method is what they were using. SInce the hammers bored your way hit the strings at 90 to the string plane instead of the keybed, these actions under that scenario only appear to be over centering . If we are taking the string height minus the center pin height they're percieved to be correct with the keybed but to the string plane...undercentering .
   Since there is often a certain amount upward string slope towards the rear of the piano the perceived over centering could vary depending on that degree of angle. Boring hammers your  way may  allow for  a straight or straighter strike line.
 Hmmm is that straight?
I'll experiment on the next N.Y. Stwy and see how it turn out. Ed do you hang curved strike lines even with this method?


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: Ed Foote <a440a at aol.com>
To: caut <caut at ptg.org>
Sent: Wed, Dec 26, 2012 8:32 am
Subject: Re: [CAUT] S&S M Strike point



Greetings,
     I'm with Dale on this one.  I always bore my hammers to any given 
piano so that they strike the strings at 90 degrees. Certain Bechsteins 
are the exception...
       I ascertain the length of bore by using pre mounted, wooden 
"hammers" (which are simply short lengths of the Renner slats used to 
ship their parts which are glued on spare Steinway shanks), which I 
know are glued on at 90 degrees to the shank. These trial dummies are 
of different lengths, and  the possible deviation of parallel between 
the keyed and the string plane is automatically taken into account. 
When the correct length is against the string, I can see the 90 degrees 
by using a square laid on the strings and extending down alongside the 
dummy "hammer", which has its centerline clearly marked.   This dummy 
also tells me how much clearance there is between the shank and the 
rest felt when the proper blow is set. They also tell me if I am 
heading into trouble inre the positions of the let-off button and drop 
screw.
    The departure from a straight strike line that is usual on larger 
Steinways is greater than can usually be accommodated by keeping a 
straight hammer line and allowing the over centering that will occur in 
these sections to shorten the strike line.
    Also, I think it is a mistake to hang hammers using the jigs on 
which the back shoulder of the hammer and the tail are used to align 
them.  The non-even taper of hammer sets will cause the hammers between 
the end indexing hammers to lean to far distal in that method.  This is 
usually only a consideration between C5 and around C7.
Regards,
Ed Foote RPT
http://www.piano-tuners.org/edfoote/well_tempered_piano.html



 
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