[CAUT] Shank to Hammer weight spreadsheet

[David Love]

I guess I haven't found that kind of variation in the shank weight (at least
of similar diameter) to make it worth while to weigh and sort.  I'm using
pretty much exclusively Renner parts, maybe some others have more variation.
The tapering does get a fairly even weight through the hammer set and after
dry assembling and measuring SW's I'm rarely altering more than 1/3 of the
set and usually the alterations are less than .3 grams.   Mostly, I try to
go up rather than down since once I'm through tapering the set, I prefer not
to go back but if I do it's rarely for more than a couple of tenths and has
no ill effects in terms of appearance.  

 

Are you suggesting that it may matter whether the SW distributional
difference of even, say, .5 grams matters whether it's located in the shank
versus the hammer in terms of inertia?  Hard to imagine at that level that
would really make any perceptible difference since some portion of that
additional weight in the shank would have to be distributed out toward the
hammer anyway, one would assume.

 

If you wanted to get very picky about potential tonal differences it might
be worth considering the variations in flexibility between shanks of equal
diameter.  Certainly rib flexibility (or stiffness) varies with ribs of the
same dimension, why not shanks, I suppose.  Maybe that's what the shank
resonance thing speaks to-and perhaps the weight indirectly.  At this point,
I'm not convinced that other aspects of tonal variation (like soundboard
resonances for example) so complicate teasing out that variable that it's
worth the trouble.  At a certain point, no matter what you do, voicing needs
to be the last line of defense.  The point at which each tech decides to put
that into play, of course, will vary.  

 

David Love
davidlovepianos at comcast.net
www.davidlovepianos.com 

-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Jon
Page
Sent: Tuesday, February 19, 2008 8:52 AM
To: caut at ptg.org
Subject: [CAUT] Shank to Hammer weight spreadsheet

 

...Once I'm done with that I simply dry assemble the shanks and hammers and

then use the Stanwood scale to weigh the SWs.  I chart those and then figure

out where I have to alter them to achieve a smooth curve...

 

I seems you are 'final fitting' your SW irrespective of the shank strike
weight (SSW).

If you initially taper your hammers to a close margin, then you are throwing

the curve off with jumbled shanks and changing the mass of the hammer due

to shank irregulatities.

 

It would be more advantageous to match similiar SSW groups to your hammers

which have been mass calibrated, thus reducing alteration. Ultimately, this
is

the most thorough method ineritally speaking.

 

I simply mate the SSW with hammer weight to target a curve because does it

really matter since it is at the end of the compound leverage system.  Are
you

feeling hammer inertia or weight at the front of the key.  Or what degree is
it

important (inertia at the end of the system) ans opposed to good inertial

effect at the front of the key.

-- 


Regards,

Jon Page

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