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What is your opinion about carbon fiber action used in pianos like Kawai and M&H?

This is settled debate. They are as good or better than wood components. As to whether or not they perform well, that will depend on whether or not the action has been regulated well, which is just as true for wood parts.

Greetings,
I don't think it is settled, at all. Tradition has its proponents, and that will not change. Controversy will surround these new parts for a while, but they are certainly proving themselves in use. There is a large industry, heavily invested in wooden parts that can only view them as a threat, and we should expect to hear a lot of reasons for staying with what is traditional, (wood is the traditional material for golf clubs, too) None of them impress me or my customers.

I have begun using them, and there is no comparison between them and wood. One is stable,the other warps and twists. One is consistent, the other, never. but the biggest reason is the pinning. Technical to work with, (more so than cloth), it provides greater stability with far less friction, and with a consistency that traditional pinning has never, in my experience, approached.
Things like stability and consistency are more important than staying with 200 year old materials, and I do believe that Cristofori would never have used wood if he had had carbon fiber or nylon.
Regards,

That may be. However, no one has managed to suggest any credible design criterion where wood excels over the currently available synthetic components. It is possible to say that a person likes wood because it has mystical vibrations but it is not possible to say that wood is preferable because it is more durable, more stable, more consistent or any other pragmatic factor that matters.

Also, I'm finding synthetic parts in pianos well over 40 years old that are showing no problems whatsoever. Good synthetic is definitely not new and unproven.
In fact, there is only one example of plastic in pianos that failed -- the first polystyrene (or whatever) that was used in the '40s and '50s in jacks, flanges, damper levers, backchecks and, most notably, elbows. Everything used since still works -- even S&S teflon that's still around.

With well regulated actions, I don't notice much difference as a pianist. If they are better from a maintenance standpoint, why not? Some people get all wrapped up in tradition. I like real Christmas trees, but I'm open to new things too.

I haven't played the WNG yet, but the Kawai BLK is great.

You may indeed be finding this, on occasion I find it too. However, it is exactly the countless problems and poor lifespan and performance of all kinds of synthetic parts and materials in pianos over 40 years old that has scared consumers and put so much grist to the mill of those who prefer wooden action parts. So I think that pointing to the plastics of over 40 years ago as a positive example does not do justice to modern plastics, which are certainly much more durable and dependable.

Ico, if you search the archives (top left hand corner of every page) you will find many discussions and some good information about the question you ask.
Welcome to Piano World. Are you a piano technician?

Everyone compares mechanical aspects. But, how different do they sound? My thinking follows with Kawai keeping the wooden shanks.

Has anyone experimented with composite hammer moldings?

Supply,

I'm not a piano technician but an amateur pianist.
I thank you all for the informations, which will be very important in my decision to buy a grand piano.

This is only an issue with higher frequencies, and in my experience, it is mitigated by using less firm hammers. Even with harder hammers, it is probably not something most people would notice.

I have put WNG shank/flanges on several pianos over the last four years. They are definitely superior to felt bushed wood. The increased stiffness and stability keep the tone-regulation very precise. No drifting of spacing and unison phasing. The greater rotational stiffness mostly eliminates the loss of unison phasing that wood shanks are prone to when playing with great force. Across the compass the even dynamic response is a joy to feel. If the tone regulator reduces the treble hammer mass properly when installing hammers-the tone is open and singing.

Some techs have complained about click noises but I think they probably cracked the shank, glue-starved a hammer joint, and/or damaged the bushing without realizing it.

The action centers are very stable. If you need to re-pin them (which will probably only be needed if you damage them installing hammers or servicing the action), the factory method is slow and cumbersome.

I have found it possible to use a heat gun to stress relieve the tight side or sides of a WNG hard-bushed action center. You simply put in the pin that fits the loosest side properly, pin the shank to the flange, and then heat the tight side to about 150 degrees for a second or two. They resize and do not creep from there.

The gel super glue WNG sends to install hammers is a bother. I use their drill bit to bore the hammers then dry fit the hammers into position and then wick thin super glue from the front and back of the hammer hole. Protect the action parts below with a barrier so no errant drips land on whippens, keys, felts, etc. You do not get a glue collar but If my reputation suffers for that sin-you can put your opinion where the sun don't shine!

The knuckles are squeakless so far and the hammer return noise is very low.

The first generation parts with the wool bushing I would not use because they reacted to humidity at almost twice the rate of change that a wood/felt combination does. I was very pleasantly surprised at how quickly they changed gears on the wool action centers. It wasn't six months after I reported to Mark Burgett the results of a comparative humidity response test that I performed on the cloth-bushed parts that WNG introduced the hard bushing.

The synthetics of 40 years ago I was speaking of are "modern". I was surprised to see a nylon jack in a Yamaha and checked the age. It was over 40 years. Also, Kawai's styran has been around over 40 years. They only started putting black pigment in it more recently, but what they are using now is similar to the styran they started with. (Styran and styrene are not the same, btw, just to be clear).

This is not to say that the formulas haven't been tweaked but that the basic chemistry of modern plastics can be found in pianos that old. Carbon fiber reinforced epoxy is new in pianos, of course.

Yes, I have had a couple of clicks that turned out to be from glue-starved hammer joints. Getting a proper joint takes a little extra attention and a change from wood-glue technique.



Yes, the factory method is slow, but not outrageously so. WNG has deprecated the heat approach to freeing up bushings. Mark says the bushings don't look pretty under a microscope after doing that. I personally have not found the heat gun approach to be reliable. The chemistry is such that heat actually expands the material.



Interesting approach! I have been playing with using two different viscosities of glue -- their gel and a "thick" liquid CA. I would personally be inclined to use wood glue as they originally did. They deprecated that practice, but the problem was in the installation -- once the glue starts to dry, you can't touch the hammer until it is completely dry.



I think their intention was always to use hard centers. I think their development and testing must have already been in progress when you made your report because I believe they spent much more than 6 months in development. But, yes, they are very responsive to technician input and I'm sure your report was helpful to them. I know they were quick to respond with a little groove in the top of the shank butt when I reported that the hammers wouldn't stay in an upright position to get access to regulating the wippen with some models of shanks.

Certainly the WNG parts have not been without their minor issues, but service and responsiveness has been stellar. Much better than the "we made it so you must be wrong" attitude that prevails in some other places.

Ed,

Are these "hard" bushings essentially just a hole of the exact dimension, or is there some type of lining (sleeve) between the hole and the center pin, made of a different material than the flange?

WNG uses a proprietary material for bushing; they don't disclose what it is, but it is not Teflon, and it is not the same material as the flange.

They are 2 different things as Kawai kept the wood for the hammer shank.

An action can be too powerful or give the impression of bein.
I believe the shank flex is providing a part of the spectrum modification we have at the piano (by changing strike point, and eventually the direction the hammer is licking the wire.

As you are a pianist, what will matter to you is to have a manageable tone, so I suggest you try pianos installed with those actions and think in terms of tone dynamics and colour/touch change.

It may not be quite correct to say Kawai "kept" wood. Looking at their gradual implementation of synthetic materials in actions for over 30 years, it is clear the direction they have been moving -- which is toward an all synthetic action. It may be more correct to say that Kawai hasn't yet made the decision to change the shank as they move to a completely synthetic action.

One reason may be the assembly process itself. As has been mentioned in other threads, there have been minor issues to be overcome in gluing on hammers with the CF shanks. No real challenge for an individual technician to make adaptations but much more of a challenge in a mass production setting -- and where getting not one, but hundreds or thousands of problems out in the field would be a disaster -- both in terms of cost and negative publicity. Or, it could be they just haven't figured out the solid bushings -- which apparently are needed because the problems with wool felt bushings are increased in a synthetic structure. In any event, it is not compelling logic to offer the current state of Kawai's ongoing action development process as "proof" of anything.

Regarding "flex" . . .
There may be different opinions about the value of "flex" in the hammershank. What cannot be disputed, however, is that the flex in wooden shanks is erratically variable from note to note. Anyone familiar with wood knows that every single piece of wood is different. (If that is questioned, just cut apart several different high-quality wooden shanks and one can see for themselves.) It is simply not scientific to suppose that 88 pieces of wood with different grain structure and density will all perform the same.

It is possible to engineer CF shanks to have different amounts of "flex" -- which WN&G does with their different wall thicknesses of the CF tube for different parts of the scale. What is absolutely impossible - is to engineer wood components to be consistent. They are inherently erratic.

I find the carbon shank to send too much power. Makes in the end a difference in tone managment (more straight)

I was just saying the 2 actions are different because of that.

That said I will not take Kawai as my referent tone quality, an, due to the tone I heard on the pianos find on your continent, I will tend to stick with my actual references and culture.

I just cant understand why we are looking for a sound that have some transparency, while visibly you are happy as soon as the tone is long and powerful.
So yes, the US market will be the first to accept all carbon shanks probably.

But did you think that you are may be listening differently ? Judging tone differently ? (I for sure do so, due to my third ear )

Pretending that wood shanks have a whole range of resiliency in s hammer set is only partially true.

Stiffnes can be categorized in 3 ranges at large in a set, an that is enough for us we test that prior to installation, then tune the shanks by scraping them.
(that change their flexibility)


I agree that syntetics can be more even in resiliency, which is evident, but is it so important ?

If the carbon can produce a similar result than wood I ll go for it. At the moment I find it too stiff.

Plus the usual problems with wood of the molding changing with moisture, may be we should glue the felt on carbon core, to obtain hammers ?

Kawai have a huge R&D dept, they could use carbon fiber if they where finding an advantage to it, as they use synthetic parts for so long..

I think more efficient and more uniform is better.



Not sure what you are meaning here. Can you explain more?



The difference is dramatic, like night and day. As soon as you use carbon you notice it right away. What we accepted as "normal" or "natural" is immediately shown to be erratic and irregular.



No, this is not automatically true. It is like the difference between sailing a small motorboat and a large oil tanker. The small motorboat can turn on a point while the large tanker takes miles to change course. Kawai has known the advantages of synthetic for a long time. They could easily have made their current action 15 years ago. They have adopted a very cautious step-by-step evolution of their actions. They are not finished.

It is the same in manufacturing. The small individual technicians and small companies are more agile than the large companies. (M&H is tiny compared to Kawai).

For example if I make a mistake, I go out and fix it. No big deal. If M&H has a production glitch, maybe they have to fix 25 pianos. If Kawai has a problem, maybe they have to fix 25,000 pianos (or 250,000). Big companies must be much more cautious in areas that affect production complexity. They don't have to worry about synthetic components because it is all controlled and uniform. But attaching wood to synthetic takes more skill and the process is not as easily absorbed into mass production procedures.

Just a curious pianist here, has Kawai really gone to solid bushings? Do you technicians out there think we'll see more solid bushings and synthetic action components from the companies that are still stubbornly sticking to wood?

I wonder because a huge issue with my 41 year old piano (I got it when it was a young 37 year old) is that the felt bushings are all shot, making for an extremely sloppy action. But it's not just me, I know someone who had an action rebuild after just 6 years on a brand new Steinway (though he does practice more than me). I've played on a lot of pianos, and while most are not in a good state of regulation, feeling the difference between my piano after regulation and a new piano, something tells me that it's not just lack of regulation holding a lot of older pianos back, but wear.

This sort of short maintenance interval is rather annoying and silly considering the magnitude of forces these parts experience, and I'd be really glad if someday when I'm looking for a high end piano, that they'll all have a trouble free synthetic action that doesn't do weird things because the temperature dropped a little and needs new bushings several times in its lifespan.

HelloTrigalg I am unsure which bushing you talk of.

The ones that drive the keys (mortise bushings) wear and are to be changed from time to time (the ones in leather last very very long but the touch is less smooth, more noisy, a little)

The cloth bushings that are in the flanges are indeed a sensible component , as the wood used to produce the flanges.

WHen a center takes too much play (generally because the bushing have compressed on ones sie, on more old parts because the center lost a little of its surface treatment, or corroded) , then new centers are used , a little bigger.

AT some point also the solution to make the part new is really to "change the bushing" , but this is done exceptionally by rebuilders, most often they prefer to use new parts.

Some subcontractors as Abel propose to change the bushing cloth in flanges, some technicians do the job themselves but this is only when the original parts HAVE to be retained (for dimensions or availability question)

beforethen some used some oil in the bushings, and that cause problems in time when the oil change to a sticky material.

Today most technicians use Teflon based products in the bushing cloth, I stopped doing so as the Teflon can also cause other problems, as loosening the grip of the part in the wood, or asking for a new treatment every year.

We have parts quality problems when it come sto the bushing cloth, all action manufacturers have to come with solutions.
The cloth swell with moisture, 1 to 2/10 mm which are really enough to slow or stop a part.

The "plastic" flanges oblige the maker to use a very soft cloth, and to find a mix of fabrics that is not too much sensitive to moisture.

Then, (as can be noticed on Kawai) , the parts are not as tight , laterally, as with traditional wood/cloth.

Using hard bushings is not new, and seem to be difficult to set up. Many techs are saying here that the WnG hard bushings are holding well in time.

I believe they also reflect much of the impact energy in the shank, when the hammer hit the strings ( part of the energy is adbsorbed in the cloth, with the usual bushings.

Is if in fine better for the tone, I dont know, as I did not play much of those actions.

Comparisons have to be done between similar pianos with the 2 actions, I suppose this can be the caseon M&H grands.