upright hammer bore

[Keith Roberts]

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Michael, please make the subject line relate to the content. Not that =
anyone else does but as a newbie at least start that way.=20
You don't need to subtract. Just measure from the hammer center pin to =
the strings. You can't do that in a grand, the flanges are under the =
pinblock. I believe the bore angle is 3* shy of 90* instead of the 1* in =
a grand.
Somebody correct me please, and explain why the difference between a =
grand and upright. I get to give the technical on hammer boring at the =
next chapter meeting.
Keith R
  ----- Original Message -----=20
  From: michael campi=20
  To: pianotech@ptg.org=20
  Sent: Thursday, February 27, 2003 5:09 AM
  Subject: Re: Thin Epoxy


  Hi everyone, I'm a bit new to this thing so forgive me any errors in =
protocol. I am attempting to compile a comprehensive body of information =
on vertical actions and rebuilding. What I am looking for right now is =
any info on objectively determining the bore distance for upright =
hammers something along the lines of subtracting one measurement from =
another similar to what we do in grands by subtracting the height of the =
hammer flange center from string height. So if anyone out there has =
details on that sort of thing or any other vertical action geometry =
stuff I'd appreciate the input. Michael



  >From: "Delwin D Fandrich"=20
  >Reply-To: Pianotech=20
  >To: "Pianotech"=20
  >Subject: Re: Thin Epoxy=20
  >Date: Wed, 26 Feb 2003 22:49:58 -0800=20
  >=20
  >=20
  >----- Original Message -----=20
  >From: "Farrell"=20
  >To:=20
  >Sent: February 26, 2003 7:54 PM=20
  >Subject: Thin Epoxy=20
  >=20
  >=20
  > > I ran across this site and thought of Del and Ron N. and Ron O. =
They are=20
  >out by Del. The topic of low viscosity epoxies has come up on the =
list=20
  >often.=20
  > >=20
  > > http://www.rotdoctor.com/products/product.html=20
  > >=20
  > > A couple very interesting products:=20
  > >=20
  > > - CPEST (Clear Penetrating Epoxy Sealer)=20
  > > - Tropical Hardwood Epoxy AdhesiveT=20
  > >=20
  > > The sealer is said to be of diesel fuel viscosity and penetrates =
into wood=20
  >way more than other epoxies (laminating bridge caps - your soundboard =

  >coating thing). They also claim that WestSystem is petroleum based =
and cures=20
  >brittle (I certainly agree that it is brittle).They say their epoxy =
is wood=20
  >based and cures flexible. I'm not sure exactly how that might =
benefit/effect=20
  >our work on pianos, but there it is (in a bridge cap, I don't see =
where it=20
  >would make much difference - brittle or flexible). The penetrating =
sealer=20
  >really gets my interest. Hmmm. Maybe we can laminate a thin strip of =
Kevlar=20
  >into those bridge caps and use this penetrating sealer for the =
ultimate=20
  >bridge cap - 'course it might be a bit of work to get a pin in it and =
to=20
  >notch it.=20
  >------------------------------------------------------=20
  >=20
  >=20
  >I am aware of this product, but have not used it. I've been just a =
bit=20
  >apprehensive, mostly because I consider the advertising and =
promotion, along=20
  >with the so-called comparison tests, to be just a little bit =
misleading.=20
  >Basically, CPEST is a solvent-thinned epoxy resin. The major =
difference=20
  >between this and other standard structural epoxies is that CPEST is =
supplied=20
  >pre-thinned. In these 'tests' only its penetrating capability, not =
its=20
  >structural strength, is being compared, yet the other standard,=20
  >multi-purpose coating and penetrating epoxies have not been thinned =
to=20
  >anywhere close to the viscosity of CPEST. I suspect that if the other =

  >epoxies had been thinned out with their appropriate solvents to the =
same=20
  >viscosity as CPEST they would have penetrated much better than is =
indicated=20
  >in this test. They would also loose some of their structural =
strength, as=20
  >does, I suspect, Dr Rot. But this characteristic is not tested. You =
may=20
  >notice that CPEST is not really being marketed as a structural epoxy =
while=20
  >the others are. In terms of flexibility, if structural epoxies such =
as WEST=20
  >System or System Three structural epoxies significantly they cure to =
a=20
  >somewhat more flexible state as well.=20
  >=20
  >So, what have we? I suspect that CPEST is a basic structural epoxy =
thinned=20
  >with whatever thinners are appropriate for the resin/hardener system =
and=20
  >sold as a thin, penetrating epoxy sealer that is "strong." Before =
becoming a=20
  >believer I would like to read an independent analysis of the =
material.=20
  >=20
  >Besides, in the soundboard work I've been doing I don't want the kind =
of=20
  >penetration being described by Dr Rot. These boards are not rotten, =
they are=20
  >structurally and stiffness impaired. I want all of the structural =
strength=20
  >and stiffness I can get. O.K., within reason.=20
  >=20
  >Del=20
  >=20
  >_______________________________________________=20
  >pianotech list info: https://www.moypiano.com/resources/#archives=20


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