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Hi,
I guess Del is the only one that can answer this, but chime in if you have an idea.

I was looking at the design of my CW grand (I love figuring out how a grand works - amazing piece of construction), and noticed that all the center plate bolts (ones away from the edges) which anchor under the SB into the belly braces, do so not ON the braces, but into a block screwed into an adjacent brace.

At first I thought it was because the braces weren't convienantly placed, but then thought that with a small shift (1-2") of the braces it would have been fine. The more I look at it, it seems to have been done on purpose. My curiosity is piqued, I think most pianos imbed the bolts directly into the braces. Doing it off an attached block adds manufacturing steps, so it must be for a reason.

There are three or so plate bolts which attach to blocks, which are attached to the belly braces via glue, and four bolts. Thoughts?

I've been rebuilding pianos for 45 years and I want to know the answer to this one! The same "block" is found on many other brands.

There has to be a good reason and it is......

I remember Charles Walter explaining his 'improvement' of the grand, but I only caught it in passing. It had to do with a 'tongue' connected to the inner brace (or plate?). I wonder if that's what you're seeing? As I recall, you could see it under the strings about mid-treble, just past the bearing bar. I'm sure the dealers of Chas. Walter can explain it better.

Eric, are you refering to the plate "keel"?

I dunno. I guess so. Does it look like a toungue :p ? What exactly is it?

p.s. I've always wanted to use that Graemlin

Eric,
I think you're talking about the "soundboard cutoff bar". I heard it used to be on top of the soundboard, under the strings, but for marketing reasons ("Whut the heck is that!!!") they put it under the piano.

The cutoff bar (from my understanding) prevents the part of the soundboard in the lower bass region (players position, it's the lower left hand corner) from participating as part of the soundboard assembly. I believe Del measured a soundboard once and found that without such a device, the board will oscillate, such that wave energy will travel from the upper right to lower left, and back and forth again over and over. The net effect is that it doesn't contribute to soundproduction and just wastes energy (reducing sustain presumably)

Del uses them all over, his rebuilds often have them in there. Another advantage to putting it on the under side (other than for looks) is that they anchored it also to the belly brace for greater rigidity (well, they could have done this when it was up top too)

On the CW grand, that dead portion of the SB still has some vestigal ribs for looks. I've verified that when the piano sounds, that part of the board is pretty dead.

The "keel" is a part of the plate that juts down near the back of the keybed. There is usually a small wedge that fits between the keel and the metal box of the "tone collector system" of Yamahas and other Asian makes. I'm not sure which makers use the keel. I was told that it supposedly "unifies" the plate to the beaming assembly and increases sustain.

I may all be sales crap, but that's what I heard!!!

So, Dan M., what's it look like? A keel that is shaped like a tounge :p , or a soundboard cutoff bar that's hidden like an ugly stepchild ?

OK OK you knuckleheads ... here's a piccy

here you see a Dampp chaser, the SB cutoff bar (lower right) and the anchor block (middle left)

Neither of which is the plate keel I was refering to!!!

Where is Del when we need him???? He's got a lot of nerve...not monitoring the Forum 24/7!!!

we need an electro-shock device attached to a pager. Then Frank can run a software script (hey - I'll volunteer my time for that) that checks for Del's name in the Forums. Whenever it comes up, he gets a friendly reminder to check in.

Yea?? (duck, quickly duck)

Just crawled under my piano... it has got those extra wood blocks too. Yeah, curious why it's done that way.

Bolts occasionally break. The side block makes it possible to remove them without removing the whole plate (including the strings, pinblock, etc.) Nothing magical. Experience has indicated that they are probably overkill -- the hardened bolts now being used don't break (ever!) -- and they will not be used on the new Model 175.

Del

Those soft old nosebolts used to break a lot.

Del

Ah! Now we're talking about something else. What you're referring to here is the steel extension going from the bottom of the plate at the bass/tenor break and extending over the top of the bellyrail. This serves to stabilize the plate to some extent. The plate is quite strong enough without it but it does deflect some once string tension is applied. All plates do unless there is some coupling mechanism of this type. This extension prevents most of that deflection.

Del

The soundboard cutoff bar is yet another different thing. This is a wood bar that physically limits and defines the size and shape of the soundboard assembly. It is placed under the soundboard panel so that it can be made part of the solid structure of the piano. It is glued and screwed and/or doweled to the inner rim, the belly braces and the bellyrail. It is structural. In the Walter it is made of laminated maple. Sometimes there is also a maple cap that sisters the cutoff bar but goes over the top of the soundboard. These bars — if they are done right — effectively take out the front (the front of the piano is always the “front” whether you’re talking about the lid, the keys, the soundboard, or whatever) bass corner of the soundboard assembly.

I’ve measured a lot of soundboards and, yes, they pretty much all vibrate (resonate) uncontrollably throughout this region of the soundboard assembly. It is a common misconception that piano soundboards should be ‘resonant.’ In fact, soundboard resonances (if they are strong enough — and many are) are voicing problems. The soundboard cutoff bar eliminates many of these spurious resonances and makes the soundboard assembly somewhat more efficient. It’s not magic, but it does help. And the piano soundboard can use all the help it can get!

The vestigial ribs you refer to are there simply to keep the soundboard panel from cracking. We’ve learned (the hard way) over the years that without these rib extensions cracks can develop in this area. Even though it is not part of the active soundboard any crack appearing in the pristine surface of what appears from the top of the piano to be soundboard strikes fear. . . .
Del

The tone collector idea actually came from Steinway. (Which reminds me of a story — I was looking at the inside of a newly introduced Yamaha grand along with a bunch of other folks at a PTG convention some 20 or 30 years back and thinking to myself how much these things were beginning to resemble Steinway pianos. At least physically if not acoustically. The Yamaha rep was explaining all of the "new" features to be found in the piano and eventually came around to the "tone collector" part. His explanation of how Yamaha had just invented this stuff, and specifically this new ‘tone collector’ device, finally got to the gentleman standing next to me. He allowed as how it was actually one of his ancestors who had first introduced most of this technology to the piano industry and that surly Yamaha was simply borrowing from the designs of an earlier age. After allowing a bit of flustered confusion and embarrassment (at least there certainly should have been some embarrassment) the gentleman next to me introduced himself — he was John Steinway.)

Still, and with respect to Mr Steinway, the whole idea of the ‘tone collector’ is, indeed, marketing hype. At least the name is. This device, along with the ‘horn’ cast into the Steinway plate, helps to couple some of the stress from the taut strings down to the bellybraces. Again, nothing magical, just a simple and effective means of stabilizing the plate.

Del

And all nicely finished off, I see.

Del

He's been working. Neither piano rebuilding nor piano design brings in enough money to allow a life of leisure. Sad, but true.

Del

Awww, damn .... I hopedit was some 'magic tone collector/diffusor' ... That makes sense however.

Thanks Del!

Del,
Are you talking about this jobbie?



The rectangular extension with the nose bolt through it?

Dan

[QUOTE]Originally posted by Dan M:
[qb] Del,
Are you talking about this jobbie?

(See earlier picture...snip.)

The rectangular extension with the nose bolt through it?

Dan


Yes.

Del

Dan,

You have way too much time on your hands, to strong an obsession with your particular strain of piano and could remedy much of your troubles by stopping by your nearest piano store to get your prescribed fill of answers...

Del,

according to your tag-line: violence then should be the first course of action for those not in the least, incompetent. Asimov is either describing or ascribing character to violence or incompetence...

Thanks Del!