capstan spacing

[Isaac OLEG]

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Hello,

I guess it is for friction and efficiency reasons, the alignment I talk of
is as seen from above (the line between capstan and front pin emplacement).

Even with the bends the balance pin in fact, may be on the line between
capstan and front pin, if the placement is optimal.

I believe that this is the cause for extra friction and added wear if too
much out of alignment ( it is found often, particularly on cheaper
instruments or little pianos).

Then, if a capstan is not centered on the middle of a key, like you state
(from left/right side) , I believe it is more due to a problem when the
wooden panel was sawed to cut the keys, than a problem with the original
placement of the capstan, the capstan holes being located before the key are
cut from the plank.

The balance holes are drilled before key cutting , and I was said they are
drilled at the same time that the balance rail (clamped together) - that
make sense for alignment reasons.
Did you check the alignment I talk of ?

Best Regards.

Isaac

-----Message d'origine-----
De : Allen Wright [mailto:awright440@cinci.rr.com]
Envoyé : vendredi 6 août 2004 17:35
À : oleg-i@noos.fr; College and University Technicians
Objet : Re: capstan spacing


Isaac,

But how about the keys that have bends by design (bass and treble)? They
certainly don't line up.

Allen

Allen
On Thursday, August 5, 2004, at 03:41 AM, Isaac OLEG wrote:


  Ask some design oriented guys more experienced than me, but seem to me
that the goal in placing capstan and pins is to align them on a straight
line (front pin, balance pin / capstan) while this ideal situation is not
always possible indeed.

  Isaac OLEG


  -----Message d'origine-----
  De : caut-bounces@ptg.org [mailto:caut-bounces@ptg.org]De la part de Allen
Wright
  Envoyé : jeudi 5 août 2004 03:28
  À : College and University Technicians
  Objet : Re: capstan spacing

  Wim and Vince,

  My question would be, what happens to the spacing of the rep to the hammer
shank/knuckle after these acrobatics you mention?

  I certainly shim the whip flange in order to space the lever to the hammer
flange, but I prefer to keep the top of the rep lever as horizontal as much
as possible, and not tilt the lever off of 90 degrees if I can help it.

  But what I'm really getting at is this: I notice quite a few of the
capstans I've removed were slightly off center of the keys anyway, and not
always in the right direction (making the capstan spacing noticeably off).
It just seems to make sense to me to take advantage of the opportunity
(while drilling new capstan holes) to see where the whip heels are when all
the action parts are properly spaced to the strings (particularly in the
bass and tenor, where the strings can't be moved) and drill capstans off
center purposely in the right direction.

  Probably even just some form of eyeballing the relationship of the whip
heels to the keys could be used to mark where to drill the capstan holes. I
wondered though if anyone has thought about this and perhaps come up with a
real accurate way to do it.

  I also wonder if there is any reason why slightly off-center capstans
could be a bad idea, in terms of geometry or wear. Perhaps more wear on one
side of the keybushings? I imagine that would be subtle if noticeable at
all.

  Any comments will be appreciated.

  Cheers,

  Allen Wright
  Northern Kentucky University
  On Wednesday, August 4, 2004, at 03:28 PM, Wimblees@aol.com wrote:

  In a message dated 8/4/04 11:15:10 AM Central Daylight Time,
awright440@cinci.rr.com writes:

  I
  noticed before removing the capstans that quite a few of them aren't
  centered perfectly to the whip heels, some being quite noticeably off
  to one side or the other. The rep levers are spaced to the hammer
  shanks accurately (with the hammers spaced to the strings).


  Alan

  You can try to center the cushions over the capstans by tilting the wips.
You might need to paper the flange to do that, just like you paper one
corner of a hammer flange to move the hammer to the right or lift. (not the
same as traveling).

  The other way to center the capstan under the wippen is to move the front
of the key. I just did this on an older D. There were quite a few capstans
that were not center under the wippen cushions. So after I tilted the wips
as much as I could, I moved the front of the key slightly, and moving some
of the keys around them to make sure the keys were still evenly spaced.
Also, make sure the keys are level. That can also effect the centering of
the capstan.

  Wim
  Willem Blees, RPT
  Piano tuner/technician
  School of Music
  University of Alabama


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