pin comparisons

[Erwinspiano@AOL.COM]

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In a message dated 1/26/2002 9:24:22 AM Pacific Standard Time, 
RNossaman@KSCABLE.com writes:


> Subj:Re: pin comparisons 
> Date:1/26/2002 9:24:22 AM Pacific Standard Time
> From:<A HREF="mailto:RNossaman@KSCABLE.com">RNossaman@KSCABLE.com</A>
> Reply-to:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A>
> To:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A>
> Sent from the Internet 
> 
>      Ron 

 I'll add one caveat and that is that I always so far for years have used(the 
low density )Buldoc or Steiway maple 1/4 sawn blocks. This doesn't change 
what your post said just stating my frame of reference. It would be difficult 
to describe maple as unrelenting ,as you characterized the baldwin block, 
unless the pinblock was set up by Morons from piano rebuilders 
anonymous,OOOOOOOOOo did I say that. Oh yes, of which I am the founder .   
      Be that as it may your comments ar all relevant and emphazizes my point 
that pin fit is critical to ease of tuning and tuning stability regardless of 
size. You all know what I mean. Just think of the pianos you tune, I bet you 
dislike the ones with pins that fight you even though the piano sounds great 
as opposed to the not so good sounding one that renders easily. Pesonally I 
want both and haven't always gotten it.
Does this make any sense today?
 >>>>>>>>>>>>>>>>>>Dale Erwin
> 
> > Dale writes: 
> > To my mind it doesn't really 
> >matter how   .   big the pin is, within reason  a no.1 thru 4 pin as long 
> >> as they render easily in the    block. know what I mean.
> > I think so. 
> 
> The fitting of the smaller diameter pin in the block is slightly less
> critical because of the smaller surface area. A a given PSI change in block
> fit will translate to a greater difference in feel at the lever handle with
> a large diameter pin than with a smaller diameter. Torque readings (and
> feel) will change less with humidity swings with the smaller pins. This is
> less noticeable in the low density blocks because there is more resilience
> to the material, so the friction gradient isn't as steep as in the high
> density blocks that don't compress as easily. At least that is the way I
> read it.
> 
> I compute ratios of block fit PSI to torque readings at the end of a 10"
> lever at:
> 1/0 1.0
> 2/0 1.044
> 3/0 1.074
> 4/0 1.112
> 5/0 1.150
> 6/0 1.189  
> 
> No, I don't have a way to measure PSI of the block fit at the pin. I judge
> them by feel like everyone else, but this is what the math shows, and it
> fits my observations through the years.
> 
>   Ed Foote wrote:
> > Given the amount of pitch change to be had without 
> >moving the pin in a usual Baldwin block,  there has to be a lot of give in 
> 
> >the system SOMEWHERE!  
> 
> There is both flex and torsion (twist). Most of the give in that Baldwin
> system is torsion in the very tight pins in the relentlessly unresilient
> block. Put those pins back in the vise and measure how far the end of the
> lever handle moves from pin twist between no load, and that ten pounds
> applied tangent to pin rotation. Then apply (by feel, and considerably more
> than ten pounds) the pull you would expect it to take to turn a Baldwin pin
> (up or down average) and measure that. A small diameter pin in a tight
> block will twist a long way at the top before the torque in the pin
> overcomes the static friction at the bottom of the pin. A large diameter
> pin doesn't twist as easily, so the bottom will move sooner. When the
> static friction between the pin and block is significantly higher than the
> sliding friction, both pins will snap in the block as they move, but the
> smaller diameter seems to snap less.   
> 
> My call.
> 
> Ron 


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