hearts on fire NOT OT

[Nichols]

At 09:38 PM 2/18/2004 -0500, you wrote:
>Guy writes:
><<  Don't be 'fraid. By now you've seen Carl's post.
>
>Too late, I have already been back to the shop to check for a crack three
>times.

Sorrrry!!......<G> (I've skeert bigger kids than You!)
Really, Ed.... Didn't mean to add tension, so-to-speak.

>  I wonder if the cracked plates in others have been caused by the tension
>on the scaling or poor fitting of plate between the pinblock, rim, and
>nosebolts.

I honestly think it's the scaling. We've seen those (about half-a-dozen) in 
all forms. Broken when they come in, broken previously and fixed, we've 
broken the dern things during disassembly, AND.... we've broken them when 
we strung 'em up with the original scale. It's a plant, not a shop, so..... 
sometimes it takes a while to learn a lesson. All of them, by the way, have 
turned out fine. And as plate cracks go, pretty easy to fix. Structurally 
and cosmetically.

>  Sheer compression,(not shear), doesn't seem like it could cause that sort
>of damage. Unless the upward force caused by the angle formed between v-bar
>and tuning pin could do it.

Must be, I'm thinkin', because the tear-down records don't indicate a 
particularly poor fit. Not compared to some of the S&S plates. (BTW... the 
guys call them "Harpas", with the "H" pretty much silent. Sounds..... 
pretty... %^) ... )

>    While I'm at it, this plate is really heavy in the capo section, with
>holes through the casting for each tri-chord.  I haven't had time to 
>examine it,
>but I wonder what the pressure surface actually is in there.

That pierced-bar segment may actually be a detriment, by not allowing a bit 
of flex. Dunno.

>
> >> I suspect
>that yours will be fine, if you let it down easy (not the old cutoff wheel
>approach) and at least rescale the treble. How about the soundboard wave.
>There? >>
>
>  Haven't seen the wave, yet, but haven't measured for it.  I usually take 
> the
>tension down on a piano by loosening one string of each note,from top to
>bottom, then doing another.  I don't let them down all the way, since I 
>cut the
>beckets with a hollow punch and a little tension on them helps to get a clean
>cut.

Awww.... you mean you don't pad the rim and shoot the bass wires over the 
fence? Where's your sense of neighborhood nuclear superiority?

>    After the strings are off, I then carefully back out the screws and bolts
>in a scattered pattern.  I have found some pianos that were built with a
>tremendous amount of flex in the plate and I wondered why they didn't 
>break upon
>assembly.  I ususally find some way of re-installing them with a little 
>more of
>a relaxed and unstressed fit.  Often, it only takes a couple of degrees of
>pinblock tilt to radically reduce the stress on the plate between block 
>and rim.

Sometimes I wish I could see the tuning history of some of the rebuilds. 
"Tremendous amount of flex" is putting it lightly, as you've seen. I wonder 
if the pianos that were assembled with a lot of flex were more-or-less 
tuning stable. I can't imagine any good reason to add stress intentionally, 
but then again... look at what happens to wood tone when we stress it 
enough. Perhaps when there's a twist, (the most common stress I've seen), 
it does something to the struts to help induce the famous bell tone. (hah 
hah) I prefer to see them so relaxed at torque-time that a solid thump has 
no corresponding woody percussion. "Dead", so-to-speak. There's plenty of 
rims, (not so much the S&S) that measurably flex if the plate is pulling on 
them. Wurlys, fer instance.


>   I will be careful, but first I am going to get Carl's scale and see how 
> far
>off this one is.  Will be in touch, and thanks to all that have been here
>before!

Yeah, I wanna see Carl's scale, also. Ain't he great?!?

>Regards,
>Ed Foote RPT

G'night,
Guy