Bechstein hammer bore

[A440A at aol.com]

JD writes: 
<<  You'll get 

>away with it through most of the scale but in the treble not only is 

>it critical to have a right angle but if you don't measure the slope 

>of the strings you won't be able to calculate it so that you do get a 

>right angle.  >>

Greetings, 
   I don't waste time measuring the angle of the strings. I simply use a 
small square on the strings, and use trial hammers, with their center line clearly 
marked and hung at 90 degrees to the shank.  By bringing this hammer up to 
the string, and then putting the square on the strings with the leg going down 
by the hammer, it is very simple to find which bore distance creates a contact 
situation with the hammershank parallel to the string and the hammer at 90 
degrees to both shank and string. For Steinways, which compromise 90% of my 
rebuilding, I have a set of trial hammers hung at 43-50mm for the treble, and 
50-58mm for the bass.  On instruments that will see extra heavy use, I usually bore 
a full mm longer than optimum, which will allow for the maximum wear in the 
"efficient" zone before needing replacement. 
   On some pianos, the upper treble strings rise so steeply to the bridge 
that the hammer would have to be bored way too short to achieve this 90 degrees 
by itself, causing a whole train of regulation problems.  In these cases, I 
have found that hanging the hammer at a little less than 90 will allow the 
hammer/string angle to be 90 degrees and the shank still to be near enough the rest 
cushion to avoid catastrophic failure under fast repetition. 
Regards,  
Ed Foote RPT 
http://www.uk-piano.org/edfoote/index.html
www.uk-piano.org/edfoote/well_tempered_piano.html
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