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My friend just bought a 70's vintage Baldwin "L" and I was taking a look at the bridges. I noticed that they are not solid wood, but in fact made up of several plies (plys?). I had thought that most bridge caps were solid wood, as are the ones on my older Baldwin. Is using plywood for bridge caps common? Are they maybe replacements?

I have 3 grand pianos, a 1978 Yamaha C7, with a capped bridge; a 1969 Howard/Kawai 550 (5'10") with a solid bridge; and a 1998 Baldwin R (5'8") with a solid bridge.

I'm thinking that the higher end/more expensive pianos usually have a capped bridge and the mid-range/consumer pianos have a solid bridge. But I really do not know why some do and some don't.

I would think the pianos with the capped bridge could be more easily rebuilt by recapping rather than replacing the entire bridge?

I'm sure the pros will chime in with a good answer.

Rick

Ah, good points. My old Baldwin definitely has a capped bridge. When I looked at my friend's "L", I couldn't see that delineation between the bridge cap and the bridge. It must have a single-piece bridge, but made of plywood? That strikes me as odd.

It is called a vertically laminated bridge. Your friend's Baldwin L (and Rickster's 1998 Baldwin R) have the vertically laminated bridge without a cap. The marketing idea was no glue line to inhibit the vibrations.

Much more common is a vertically laminated root with a solid cap. All Steinways have had this style for 140 years or more, Yamahas have it, old Baldwins had it, and a great many other pianos do.

Vertically laminated bridges with or without caps are more expensive to make than a solid capped bridge. Using the word plywood implies the use of inferior materials, which is not the case.

A vertically laminated bridge without a cap could be planed down and recapped, just as one would a solid bridge cap.

Yes, there it is! Sorry to use the term "plywood", I just couldn't conjur a more respectful term at the moment.

Indeed it is "vertically laminated". Thanks for the edification!

Some makes also use horizontally laminated bridge caps, Schimmel for example. These require machines to notch the bridge.

Some high end makers design for solid bridges, like Bösendorfer. I use the examples so that design choices are not automatically assumed to be related to quality. There is more than one "right way" to design pianos.

Once the hammer strikes the string, energy and information is being lost. Everything under the lid should be designed to capture as much of that information as possible. Hence soundboard quality, rim construction materials, etc...The idea behind the vertically laminated bridge is the energy produced by the string travels through a VLB faster than it does a solid bridge. So less energy is lost. All Steinway grand piano products including Boston & Essex use these types of bridges. I do not know what the theory is behind other bridges. Most manufacturers, not all, use this type of bridge on their more expensive pianos. For instance Yamaha includes it on their CX series and up, Kawai on their GX series and Shigeru etc...

On the Kawai...
http://www.kawaius.com/main_links/grands_09/gx_series/video/gx_video-treblebridge.html

It's not that simple. Many of the great pianos have had solid bridges. I would think a well made solid bridge is more difficult and expensive to produce, especially now, when long pieces of clear straight grain hardwoods are very rare.

Steve

Bridge cap material can be used for repairs too, this is a multiple ply done with very thin layers.

A massive bridge cap is considered better looking and more noble, due
To more coherence in wood, less glue,

Harder material is better in high treble, the multiple ply is may be less hard.

This is all interesting stuff. So some of the top tier manufacturers differ on which is better- or at least what they choose to use.

Then the lower tier instruments, as mentioned by Ryan- i.e. NY Steinway, Boston and Essex stick to just one system.

Manufacturer propaganda notwithstanding, I have a feeling this is the real reason many makers switched to laminated bridges. The old-growth wood simply isn't readily available as it was in the old days.

Much of the maple is too soft, it's not the rock maple of the old days. I make my own horizontally laminated bridge caps by gluing up maple veneers. I know several other rebuilders who do this.

When I need to fabricate an entire bridge it is usually for water damaged pianos. Steinway does not sell bridges. So I have to fabricate a caul to glue the vertical laminated root on. I don't put caps on the new bridges because I use Weldwood water proof glue.

I think the reason older laminated bridges have a cap is to protect the animal hide glue from direct contact with moisture, and in high humidity the glue could rust the the string. It would be very easy for slight spills to ruin a vertically laminated bridge made with hide glue. Steinway probably is concerned with tradition, so they haven't made the switch.

Baldwin's vertically laminated bridges uses water proof glue but they usually did not use adequate clamping pressure to get the strongest joint. You can usually see quite a thick glue line between laminations. On my bridges the glue lines look like wood grain.

The "sales spiel" Baldwin gives about avoiding a glue joint that can inhibit sound transmission to the soundboard is hyperbolae. There is still a glue joint between the bridge and the board after all. Or, maybe Baldwins record of less than stellar glue joint quality control played a role in their thinking.

Did some old pianos have a solid wood bridge with a solid wood cap? Or are all bridges laminated, some with caps, others not?

What kinds of wood can they use? I have to take down a pecan tree, probably about 20 - 25 ft. of straight trunk. I also have to take some limbs off some California black walnuts -- there may be some 3 - 5 ft. straight sections available. Maybe some slight curves would work even better for piano bridges.

I have seen walnut (Erard) and I've used Hickory for laminated bridge roots before. Also, Beech is popular in Europe.

Steve

Interesting extremes -- hickory is so springy, walnut is almost like a ceramic it's so hard.

If anybody wants some of the wood from my trees, I'll give it away for free.

I've used quarter-sawn maple for bridge caps. As to Baldwin, their laminated bridge survived submersion in my Katrina SD...well sort of, the glue joints were unscathed,but the water got down into the bridge pins and the corrosion destroyed the bridge from within. The pinblock likewise did not come unglued, but the water wreaked havoc in the tuning pin area. Baldwin used a lot of of high-quality laminated (I think) beech constructing their pianos in the last 20 years. The keybed is laminated beech, the bridge, the pinblock and also the lid itself were laminates.