Open face vs. closed face pin blocks

[Phillip L Ford]

     I would like to amend what I said earlier.  I said that if I were building
a piano I would lean toward an open face pinblock design.  What I
think I would prefer to use is an open face pinblock set in a plate
that is closed beneath the pinblock.  I believe Chickering (and others?)
used such a system at one time.  It seems to me that you get the tuning
advantages of the open face design but you get the stiffness of the
closed face design because you have the full depth beam in the pinblock
area of the plate.  One problem with the old Chickering design was that
it was very labor intensive to fit the pinblock to the plate (does anyone
know of other reasons for abandoning this design?).  With proper plate
design and NC machining I don't see why a design like this should
present a problem in a modern factory environment.
     Another topic which I didn't bring up before was plate bushings.  It
seems in theory that a closed plate design with plate bushings should
tune like an open face design.  The distance of the string to the plate
could be the same as the distance from the string to the pinblock in
an open face design.  However, in my experience pianos with plate
bushings feel more or less like any other closed face design without
plate bushings.  Perhaps this is because of the poor quality of the plate
bushings.  I wonder what would be the result of using bushings of good
material (say laminated maple) that fit closely to the plate and are glued
to the surface of the block.  The holes are then drilled through bushing
and pinblock at the same time so that the bushings essentially become
part of the pinblock?  I can imagine that it would be a manufacturing
nightmare.  But it might give a closed face pinblock that tunes like an
open face pinblock.

Phil
---
Phillip Ford
Piano Service & Restoration
1777 Yosemite Ave
San Francisco, CA  94124

On Wed, 15 Aug 2001 19:17:31  
 Delwin D Fandrich wrote:
>
>----- Original Message -----
>From: "Phillip L Ford" <fordpiano@lycos.com>
>To: <pianotech@ptg.org>
>Sent: August 15, 2001 9:30 PM
>Subject: Re: Open face vs. closed face pin blocks
>
>
>
>> .... Probably there is some lower limit on the amount of
>> stiffness required to give what we now consider good tone and acceptable
>> tuning stability and once you are beyond that it doesn't really matter how
>> you achieve it.
>
>I'm sure you're right. I suspect those pianos down close to that lower limit
>have long ago self-destructed. Our experience is with the survivors.
>
>
>
>> At this point I think that if I was building a piano I would lean towards
>an
>> open face design.
>
>Me to.
>
>
>
>> I feel that a stronger theoretical case could be made for capo vs.
>> agraffes but once again my personal experience has been that there
>> are some fine pianos with agraffes all the way to the top so it's pretty
>> hard for me to say that the capo design should be better.
>
>I agree. And for most of my career I have assumed that the capo d'astro bar
>system was inherently superior. And in terms of measurable numbers, they
>are. But, as I've said in earlier posts, my experience has shown that
>all-agraffe systems can work exceptionally well. Perhaps the numbers don't
>mean as much as we have long thought and/or been taught. Or, perhaps we're
>looking at the wrong numbers.
>
>
>
>> It's too
>> bad that there are so many variables that it's hard to isolate these
>specific
>> things so that they can be studied.  It would be nice (in some ways) to
>> build two pianos that were exactly the same except for the one thing that
>> you wanted to study. I can add this to my ever expanding wish list.
>
>Those lists do keep getting longer and longer, don't they.
>
>Del
>
>


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