Pianotech

Hi All,
I have a 1927 Vose and Sons Grand piano in my shop that will be getting a new Soundboard. It turns out to be a somewhat interesting soundboard.
At first glance this board looked like a keeper. It had an obvious crown, but also 4 cracks. My first thought normally, would be to just repair it.
But a previous technician did a number on it with the nails going through the bridge and sticking out the other side. Also, there was damage done to the apron. 
So today the board came out.
Now here is were it gets a little interesting.
First it only took four strikes with a 2x4 and it was out. IMO, that's hardly glued in.
Next was the rib structure which was oddly space (see pic) According to my calculations it was under massed, and also IMO needs two more ribs. Observation reveals that the widely spaced small ribs just weren't enough as the tenor break and bass bridge were "sunken" a bit and thats where the two biggest cracks are.
Now the ribs themselves. They are clearly Rib Crowned. I didn't know that they did that back in 1927. Which leads to me asking if anyone knows who invented rib crowning? Or anything regarding its history. 
Another question. The top of the rib was machine crowned, but the grain and bottom of the ribs were reverse crowned, Is that really "Crowned?"
I tried to take a pic of that, but it might be hard to discern.
So what at first appeared to be a salvageable board, turned out to have deep structural problems. I found that to be interesting.

Out the bottom.




Thanks in advance
-chris

------------------------------
I don't always play the piano, but when i do, I prefer my own.
chernobieffpiano.com
grandpianoman@protonmail.com
865-986-7720
------------------------------

"Observation reveals that the widely spaced small ribs just weren't enough as the tenor break and bass bridge were "sunken" a bit and thats where the two biggest cracks are."

If it is a compression-crowned board, the ribs don't support crown/downbearing, the panel does. Sounds like the panel failed.

"They are clearly Rib Crowned."

What makes that clear?

"The top of the rib was machine crowned..." 

How can you tell the difference between machine and hand crowning on a rib? What difference would it make anyway?

"...but the grain and bottom of the ribs were reverse crowned..."

What are you calling the bottom of the ribs - the side glued to the panel? What are you calling reverse crowned - convex?

If a soundboard is bent inside-out (top/bridge-side concave), why would you call that rib crowned? Sounds to me more like a not-uncommon failed old compression-crowned soundboard.

------------------------------
Terry Farrell
Farrell Piano Service, Inc.
Brandon, Florida
terry@farrellpiano.com
813-684-3505
------------------------------

Original Message:
Sent: 09-17-2018 10:37
From: Chris Chernobieff
Subject: RC Soundboards History and Problems?





Hi All,
I have a 1927 Vose and Sons Grand piano in my shop that will be getting a new Soundboard. It turns out to be a somewhat interesting soundboard.
At first glance this board looked like a keeper. It had an obvious crown, but also 4 cracks. My first thought normally, would be to just repair it.
But a previous technician did a number on it with the nails going through the bridge and sticking out the other side. Also, there was damage done to the apron.
So today the board came out.
Now here is were it gets a little interesting.
First it only took four strikes with a 2x4 and it was out. IMO, that's hardly glued in.
Next was the rib structure which was oddly space (see pic) According to my calculations it was under massed, and also IMO needs two more ribs. Observation reveals that the widely spaced small ribs just weren't enough as the tenor break and bass bridge were "sunken" a bit and thats where the two biggest cracks are.
Now the ribs themselves. They are clearly Rib Crowned. I didn't know that they did that back in 1927. Which leads to me asking if anyone knows who invented rib crowning? Or anything regarding its history.
Another question. The top of the rib was machine crowned, but the grain and bottom of the ribs were reverse crowned, Is that really "Crowned?"
I tried to take a pic of that, but it might be hard to discern.
So what at first appeared to be a salvageable board, turned out to have deep structural problems. I found that to be interesting.

Out the bottom.




Thanks in advance
-chris

------------------------------
I don't always play the piano, but when i do, I prefer my own.
chernobieffpiano.com
grandpianoman@protonmail.com
865-986-7720
------------------------------

Mr. Farrell,
It's a failed RC board for sure. Look closer at the rib in the pic (that rib in the pic is 3' long). The rib removed sits flat on the bench, the top of it has an arch cut into it.  I would guess a 45'- 50' radius. The top and bottom are not parallel as you would see with a rib from a CC ( funny how those are my initials). 
I don't believe the "panel" does it all" theory. If that were true, all compression board ribbing would be minimal in nature (small strips across the grain would be sufficient). But that's not what you see. Also, the ribs would be the same size. But that's not what you see either. They are graded in size, and the grading has a relationship to their length.  Hence indicating, they need to be stronger to span the longer length.

This is where the words "impedance matching" is often thrown into the conversation. Dare I say, I think riblets demonstrate that "impedance matching" occurs by adding stiffness to the fields in between the ribs. Therefore thinking minimalistic-ly, this would be better accomplished by making the (as previously mentioned cross grain strips) wide to start closing the distance in the fieds. 
But you don't see that either. 
-chris

------------------------------
I don't always play the piano, but when i do, I prefer my own.
chernobieffpiano.com
grandpianoman@protonmail.com
865-986-7720
------------------------------

Original Message:
Sent: 09-18-2018 08:28
From: Terrence Farrell
Subject: RC Soundboards History and Problems?

"Observation reveals that the widely spaced small ribs just weren't enough as the tenor break and bass bridge were "sunken" a bit and thats where the two biggest cracks are."

If it is a compression-crowned board, the ribs don't support crown/downbearing, the panel does. Sounds like the panel failed.

"They are clearly Rib Crowned."

What makes that clear?

"The top of the rib was machine crowned..." 

How can you tell the difference between machine and hand crowning on a rib? What difference would it make anyway?

"...but the grain and bottom of the ribs were reverse crowned..."

What are you calling the bottom of the ribs - the side glued to the panel? What are you calling reverse crowned - convex?

If a soundboard is bent inside-out (top/bridge-side concave), why would you call that rib crowned? Sounds to me more like a not-uncommon failed old compression-crowned soundboard.

------------------------------
Terry Farrell
Farrell Piano Service, Inc.
Brandon, Florida
terry@farrellpiano.com
813-684-3505

Original Message:
Sent: 09-17-2018 10:37
From: Chris Chernobieff
Subject: RC Soundboards History and Problems?





Hi All,
I have a 1927 Vose and Sons Grand piano in my shop that will be getting a new Soundboard. It turns out to be a somewhat interesting soundboard.
At first glance this board looked like a keeper. It had an obvious crown, but also 4 cracks. My first thought normally, would be to just repair it.
But a previous technician did a number on it with the nails going through the bridge and sticking out the other side. Also, there was damage done to the apron.
So today the board came out.
Now here is were it gets a little interesting.
First it only took four strikes with a 2x4 and it was out. IMO, that's hardly glued in.
Next was the rib structure which was oddly space (see pic) According to my calculations it was under massed, and also IMO needs two more ribs. Observation reveals that the widely spaced small ribs just weren't enough as the tenor break and bass bridge were "sunken" a bit and thats where the two biggest cracks are.
Now the ribs themselves. They are clearly Rib Crowned. I didn't know that they did that back in 1927. Which leads to me asking if anyone knows who invented rib crowning? Or anything regarding its history.
Another question. The top of the rib was machine crowned, but the grain and bottom of the ribs were reverse crowned, Is that really "Crowned?"
I tried to take a pic of that, but it might be hard to discern.
So what at first appeared to be a salvageable board, turned out to have deep structural problems. I found that to be interesting.

Out the bottom.




Thanks in advance
-chris

------------------------------
I don't always play the piano, but when i do, I prefer my own.
chernobieffpiano.com
grandpianoman@protonmail.com
865-986-7720
------------------------------

I don't think I see the photo you are referring to.

------------------------------
Ed Sutton
ed440@me.com
(980) 254-7413
------------------------------

Original Message:
Sent: 09-18-2018 10:22
From: Chris Chernobieff
Subject: RC Soundboards History and Problems?

Mr. Farrell,
It's a failed RC board for sure. Look closer at the rib in the pic (that rib in the pic is 3' long). The rib removed sits flat on the bench, the top of it has an arch cut into it.  I would guess a 45'- 50' radius. The top and bottom are not parallel as you would see with a rib from a CC ( funny how those are my initials).
I don't believe the "panel" does it all" theory. If that were true, all compression board ribbing would be minimal in nature (small strips across the grain would be sufficient). But that's not what you see. Also, the ribs would be the same size. But that's not what you see either. They are graded in size, and the grading has a relationship to their length.  Hence indicating, they need to be stronger to span the longer length.

This is where the words "impedance matching" is often thrown into the conversation. Dare I say, I think riblets demonstrate that "impedance matching" occurs by adding stiffness to the fields in between the ribs. Therefore thinking minimalistic-ly, this would be better accomplished by making the (as previously mentioned cross grain strips) wide to start closing the distance in the fieds.
But you don't see that either.
-chris

------------------------------
I don't always play the piano, but when i do, I prefer my own.
chernobieffpiano.com
grandpianoman@protonmail.com
865-986-7720

Original Message:
Sent: 09-18-2018 08:28
From: Terrence Farrell
Subject: RC Soundboards History and Problems?

"Observation reveals that the widely spaced small ribs just weren't enough as the tenor break and bass bridge were "sunken" a bit and thats where the two biggest cracks are."

If it is a compression-crowned board, the ribs don't support crown/downbearing, the panel does. Sounds like the panel failed.

"They are clearly Rib Crowned."

What makes that clear?

"The top of the rib was machine crowned..." 

How can you tell the difference between machine and hand crowning on a rib? What difference would it make anyway?

"...but the grain and bottom of the ribs were reverse crowned..."

What are you calling the bottom of the ribs - the side glued to the panel? What are you calling reverse crowned - convex?

If a soundboard is bent inside-out (top/bridge-side concave), why would you call that rib crowned? Sounds to me more like a not-uncommon failed old compression-crowned soundboard.

------------------------------
Terry Farrell
Farrell Piano Service, Inc.
Brandon, Florida
terry@farrellpiano.com
813-684-3505

Original Message:
Sent: 09-17-2018 10:37
From: Chris Chernobieff
Subject: RC Soundboards History and Problems?





Hi All,
I have a 1927 Vose and Sons Grand piano in my shop that will be getting a new Soundboard. It turns out to be a somewhat interesting soundboard.
At first glance this board looked like a keeper. It had an obvious crown, but also 4 cracks. My first thought normally, would be to just repair it.
But a previous technician did a number on it with the nails going through the bridge and sticking out the other side. Also, there was damage done to the apron.
So today the board came out.
Now here is were it gets a little interesting.
First it only took four strikes with a 2x4 and it was out. IMO, that's hardly glued in.
Next was the rib structure which was oddly space (see pic) According to my calculations it was under massed, and also IMO needs two more ribs. Observation reveals that the widely spaced small ribs just weren't enough as the tenor break and bass bridge were "sunken" a bit and thats where the two biggest cracks are.
Now the ribs themselves. They are clearly Rib Crowned. I didn't know that they did that back in 1927. Which leads to me asking if anyone knows who invented rib crowning? Or anything regarding its history.
Another question. The top of the rib was machine crowned, but the grain and bottom of the ribs were reverse crowned, Is that really "Crowned?"
I tried to take a pic of that, but it might be hard to discern.
So what at first appeared to be a salvageable board, turned out to have deep structural problems. I found that to be interesting.

Out the bottom.




Thanks in advance
-chris

------------------------------
I don't always play the piano, but when i do, I prefer my own.
chernobieffpiano.com
grandpianoman@protonmail.com
865-986-7720
------------------------------

Original Message------

I don't think I see the photo you are referring to.

------------------------------
Ed Sutton
ed440@me.com
(980) 254-7413
------------------------------

Original Message------





Hi All,
I have a 1927 Vose and Sons Grand piano in my shop that will be getting a new Soundboard. It turns out to be a somewhat interesting soundboard.
At first glance this board looked like a keeper. It had an obvious crown, but also 4 cracks. My first thought normally, would be to just repair it.
But a previous technician did a number on it with the nails going through the bridge and sticking out the other side. Also, there was damage done to the apron. 
So today the board came out.
Now here is were it gets a little interesting.
First it only took four strikes with a 2x4 and it was out. IMO, that's hardly glued in.
Next was the rib structure which was oddly space (see pic) According to my calculations it was under massed, and also IMO needs two more ribs. Observation reveals that the widely spaced small ribs just weren't enough as the tenor break and bass bridge were "sunken" a bit and thats where the two biggest cracks are.
Now the ribs themselves. They are clearly Rib Crowned. I didn't know that they did that back in 1927. Which leads to me asking if anyone knows who invented rib crowning? Or anything regarding its history. 
Another question. The top of the rib was machine crowned, but the grain and bottom of the ribs were reverse crowned, Is that really "Crowned?"
I tried to take a pic of that, but it might be hard to discern.
So what at first appeared to be a salvageable board, turned out to have deep structural problems. I found that to be interesting.

Out the bottom.




Thanks in advance
-chris

------------------------------
I don't always play the piano, but when i do, I prefer my own.
chernobieffpiano.com
grandpianoman@protonmail.com
865-986-7720
------------------------------