[pianotech] Bouncing Bostons

John Delacour JD at Pianomaker.co.uk
Fri Jul 30 12:51:07 MDT 2010


At 12:35 -0500 30/7/10, William Monroe wrote:

>To your questions and Ron's observations:
>
>I already raised the rest rail as close as is reasonable to the 
>shanks - about 1/16" gap +/-   It was lower before, and was worse 
>then, but still exists.  It's a solid (adjustable) aluminumÊrail and 
>the felt is relatively firm and relatively thin.  Blow was also even 
>more prior to regulation (close to your 47mm), and the prolem was 
>diminished by decreasing blow to 1 3/4" (roughly 44.5mm).
>
>Things are really pointing towards a too firm and too thin rest rail 
>felt, and possibly some hammer flange pinning issues.
>
>Thanks for the insight, one and all.  JD, "lever-heel," "backtouch", 
>can you clarify this nomenclature for me? ÊI'm unfamiliar with it. 
>Thank you.

The lever (Am. wippen) heel is the cushioned profile that rests on 
the capstan.  Does this have a small under-cushion under the main 
cloth?  If not, that would be another contributory factor.

The backtouch is the strip of baize or multi-layered cloth along the 
back rail of the key-frame.

With regard to the hammer centres, there is not much scope for 
improvement unless at the cost of several other problems.  It would 
be detrimental to make the centres stiffer than they should be simply 
to get rid of this inconvenience.

It may be that your backtouch also is too firm, though Steinways, 
over here at least, generally have always used a thick and quite firm 
English baize.  Some of the Chinese felts and cloths are OK but I 
have seen some pretty odd varieties too, such as very firm damper 
felt.

JD



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