[CAUT] Shank to Hammer weight spreadsheet

[Chris Solliday]

[CAUT] Shank to Hammer weight spreadsheetI think that what I do in effect is what you suggest. I just do the hammer weight calibration after assembly. So it's the strike weight calibration. I'm saying the hammer weights I have measure over the last few years are much smoother than they used to be so I'm beginning to assume (look out) that this will result in the least amount of hammer manipulation in calibration.
Thanks,
Chris
  ----- Original Message ----- 
  From: David Love 
  To: 'College and University Technicians' 
  Sent: Tuesday, February 19, 2008 12:55 PM
  Subject: Re: [CAUT] Shank to Hammer weight spreadsheet


  As an addendum to this, what makes more sense to me, if you are going to sort shanks, is to prepare the hammer set, weigh each hammer and alter the ones necessary so that the hammer weights themselves are a smooth progression.  Then weigh the SW of each shank and sort them from heaviest to lightest.  Then put the hammers and shanks together with the heaviest shank at #1 etc..  That way you will have a smooth total SW and the distributed SW relationship between shank and hammer would progress uniformly through the set.  The resonance thing does complicate things though, doesn't it?     



  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 David Love
  Sent: Tuesday, February 19, 2008 9:28 AM
  To: 'College and University Technicians'
  Subject: Re: [CAUT] Shank to Hammer weight spreadsheet



  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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