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May be with an artistic placement of the whippen at rest, the friction from the start will be enough to fight the tendency of the capstan to push the whippen from the player, which go in reverse direction of the circular motion of the whippen.

difficult to really imagine what is goin on

I have certainly come across this on the kind of pianos I deal with.

Friction is “high” compared to what? The sliding motion is almost non-existent. It really doesn’t matter much what the friction is. (Unless, of course, the geometry of the action is not correct. And then the action is going to need more than polished capstans!)




Yes, I own – and have read – Pfeiffer’s books. Felt hardness is always a compromise; too hard and the action gets noisy, too soft and too much energy is lost. And it wears out rapidly. Mostly because it packs down, gets hard and noisy fast.




Yes, I know about action efficiency and saturation. I studied the phenomenon back in the 1970s and later, during the 1980s, I found that researchers at Baldwin had also investigated this. Ultimately I wrote a couple of articles about it in the Piano Technicians Journal sometime during the 1990s.

I was thinking about all this over the weekend as I replaced a set of capstans in a small (imported) grand. The originals were very small and very round; in just a very few years they had punched a hole right through the capstan block felt and nicely indented the wood in the block.

I wonder, sometimes, how the folks making the decisions that resulted in these parts being installed in production pianos manage to keep their jobs. Both the “engineer” who approved them and the purchasing manager (who probably demanded them) really should have known better. And if they don’t they shouldn’t be in those positions.

ddf

As long as it lasts until they retire. However, I wonder about the supplier who made the capstans.

Oh, I don't think the concern lasts that long. The thing gets shipped and enough people buy them who don't really play them all that much so the warrantee costs are not all that high. The company saves a few pennies on cheaper parts and who gets caught?

And the vendor probably knows nothing at all about pianos. They are just making widgets to drawings and specifications furnished by the piano maker (or key maker).

ddf

There’s a saying, “Screw up to move up.”

Part of the reason is that once a person (hopefully) learns from their errors they are considered to be an expert. Another part of the reason is a lousy underling can make a bad boss look good by giving the boss someone to yell at and a problem to fix. But a good underling can make a bad boss look even worse by showing him up. I’ve seen it many times….

Del, I know that the sliding move is very small, what I say is that have been explained to me by one major builder, I will post you privately.

The cloth in fact take the shape of the capstan (cloth is smooth, not capstan) during the compression, there is a grip between the 2 parts. say that manufacturer. how much I hardy can imagine. I guess they envisage :
direction of force
Center of gravity of the whippen mass
Inertia

Things that are way mire difficult to evaluate than the common idea of a relatively rigid action with a few puivot points and sliding paths.

That is why I dont understand why those aspects are not mo investigated.

Ps on the Asian brand you talk of, the profile of the capstan was bad. On another one the capstans symply where not polished nor surface treated, they eat the cloth the same, in less than one year.
I dont understand why one would expect a low end asian builder to understand what he does when he symply copies an existing design.

producing a manufactured thing as a piano is certainly not magical, information is less availeable than for more usual things, so comprehension can be limited.

Del can you tell me in wich issues the articles where ? I can have a look at my collection. I recall reading about the key flex.
I like to investigate to understand what makes the roller leave the jack so soon. is it the key/ cloth compression/reaction ? is it located within the whippen ?
Certainly the reason why an optimal bedding is very important, an why the tone get so poor when bedding is screwed.

Even during a very rapid repetition?

Action saturation ! I was certainly not stating you did not knew about that, it is due to the way I write.

What was the conclusions ?

is a highe saturation level good for the control on touch ? Pfeiffer discovered that the linked action was the poorer in term of efficiency, and thatbthe freeness between the parts is necessary.

During any kind of repetitoin. The sliding motion does not change with the speed of repetition. In theory it can change slightly with the bending of the keys but the effect is minimal.

ddf

August and December, 1996

I don't think I said this was an Asian piano. It was not.

ddf

I believe he mentioned it was an imported grand.

Yes, I did say "imported." It was not, however, Asian.

ddf

Byron,

It's OK to quote me, since this was something that happened to me. I often mention it in regulation seminars because it illustrates the concept that almost everything we do to an action can be perceived as a change in tone.

One factor that might have been misunderstood from my story is that the request was after an initial rehearsal, and the pianist left for about 1/2 hour while I worked on the piano. I polished the capstans AND front keypins, and touched up unisons. When the pianist came back and tried the piano, she was very happy and said she was impressed that I could "brighten" the piano so quickly.

When I polish capstans and lube the wippen cloth with Teflon powder I can feel the difference in the touch, but it is subtle as others have said. In some cases it can be that small difference that seems to make the tone "pop" out of the piano through easier / faster accelleration of the action.

Thanks for the clarification. Now I remember, there was more to the story.

I always enjoy your seminars and get a lot out of them.

People are discussing sliding friction, but it could be that static friction is more the issue. Perhaps the lubrication of the capstans allows the parts to more easily break free from each other.

Quite a few years ago, on a whim, I tried spraying McLube into the capstan/wippen heal connection with the action still in the piano using one of those small flexible red nozzel extensions. I must have not shook the can up, because I think what happened was that the carrier sucked all the natural lubricant out of the wippen cushions. They squeeked like crazy! This was not the result I intended!! Using a hypo oiler I got some protek in there and it cured the squeeking. Maybe this piano was an anomaly, but if sliding friction is negligible, why the squeek??

There is a lot of pressure on the capstan: the whole weight of the hammer and wippen, along with the key and its lead weights conspire to hug those parts together. Once the parts are moving the friction may not be very measurable, but it would certainly contribute substantially to the static friction.

I guess you may be right.
I would never have think of that if I did not receive explanations on a particular grand action setup, where part of the concept is to optimize the direction of force between capstan and whippen because of the pulling effect on the center.

But no one seem to dare exploring that , and I see most are thinking of the action in automotive mechanic terms, as if the centers where ball bearings !

How true ! then the number of tricks/tips where we cant give a decent explanation and that are classified placebo is huge !