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#2127767 - 08/04/13 01:13 AM front key bushings regulation
pierrot Offline
Junior Member

Registered: 06/20/07
Posts: 19
Loc: japan
i just have had my tech replace all the key bushings.

according to danny boone's "regulating grand piano touch and tone", front key bushings "should allow only a perceptible sideways movement in the keys" and he considers sideways movement more than .012"(0.3mm) to be "excessive".

and i showed the tech this book and told him i wanted to have my bushings to be done that way.


now the tech brought back the keyframe with the keys fitted in, i found most of keys moved sideways more than "only perceptibly". in addition, he said he had black keys to have more sideways movement than white keys for some reason.

though i cant measure the amount of movement correctly since it is very tiny, at least black keys seem to have around 1mm of movement sideways.

he explained that recently techs at authorized steinway dealership in japan usually recommend making even more sideways movement.

so, what do you think?

i think what boone recommends is right.
in my opinion, key bushings should fit as snug as possible
as long as they dont causes unnecessary friction.

does any of you have any objections to boone's recommendations?
let me hear your thoughts.
_________________________
pardon me for asking......too much?

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#2127786 - 08/04/13 02:08 AM Re: front key bushings regulation [Re: pierrot]
beethoven986 Offline
3000 Post Club Member

Registered: 01/20/09
Posts: 3319
As little side play as possible. All key pins and capstans should be polished and lubricated to minimize friction.
_________________________
B.Mus. Piano Performance 2009
M.Mus. Piano Performance & Literature 2011
PTG Associate Member
Certified Dampp-Chaser installer

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#2127789 - 08/04/13 02:14 AM Re: front key bushings regulation [Re: pierrot]
kpembrook Offline
1000 Post Club Member

Registered: 04/06/10
Posts: 1294
Loc: Michigan
Are you an engineer?

I just ask because this is the kind of thing that engineers interested in DIY piano repair ask.

The thing to understand is that in pianos, to a large degree, function comes first and specs are an after-the-fact guide to what is likely to provide good function.

There are many considerations, including . . .
What time of year is it/what are humidity levels now and likely to be in 6 months?
What material is keypins? (Plated, anodized aluminum?)
Have the keypins been cleaned and/or lubricated?
What kind of bushing cloth has been used?
How rigid is the wood at the bushing mortise?
What is other action leverage, intertia and friction like?

The principle is that tighter tolerances do measurably increase friction and looser tolerances have more side-play -- creating sloppy touch sensation and possibly wear on the wippen heel.

In between "too little" and "too much" you have a space of some latitude that is "just right" -- or at least, "OK".

Personally, I wouldn't stress about it unless you are observing some issue as you play. The purpose of adjusting tolerances is to improve playability -- not to satisfy what somebody has written in a book, even if the book is generally on track.
_________________________
Keith Akins, RPT
USA Distributor for Isaac Cadenza hammers and Profundo Bass Strings
Supporting Piano Owners D-I-Y piano tuning and repair

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#2127827 - 08/04/13 06:44 AM Re: front key bushings regulation [Re: pierrot]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7178
Loc: France
it is about 0.4 mm for the front, but the lateral motion only is difficult to evaluate as there is also motion coming from the balance rail about 0.2 mm. under standard humidity.

leather bushing need more side play



Edited by Olek (08/04/13 06:52 AM)
_________________________
Isaac OLEG - http://picasaweb.google.fr/PianoOleg pro

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#2127843 - 08/04/13 07:49 AM Re: front key bushings regulation [Re: kpembrook]
David Jenson Offline
2000 Post Club Member

Registered: 10/22/06
Posts: 2034
Loc: Maine
Originally Posted By: kpembrook
Are you an engineer?

I just ask because this is the kind of thing that engineers interested in DIY piano repair ask.

The thing to understand is that in pianos, to a large degree, function comes first and specs are an after-the-fact guide to what is likely to provide good function.

There are many considerations, including . . .
What time of year is it/what are humidity levels now and likely to be in 6 months?
What material is keypins? (Plated, anodized aluminum?)
Have the keypins been cleaned and/or lubricated?
What kind of bushing cloth has been used?
How rigid is the wood at the bushing mortise?
What is other action leverage, intertia and friction like?

The principle is that tighter tolerances do measurably increase friction and looser tolerances have more side-play -- creating sloppy touch sensation and possibly wear on the wippen heel.

In between "too little" and "too much" you have a space of some latitude that is "just right" -- or at least, "OK".

Personally, I wouldn't stress about it unless you are observing some issue as you play. The purpose of adjusting tolerances is to improve playability -- not to satisfy what somebody has written in a book, even if the book is generally on track.
+1
_________________________
David L. Jenson
Tuning - Repairs - Refurbishing
Jenson's Piano Service
-----

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#2127852 - 08/04/13 08:17 AM Re: front key bushings regulation [Re: pierrot]
Ed Foote Offline
1000 Post Club Member

Registered: 05/03/03
Posts: 1097
Loc: Tennessee
Greetings,
Let's just start with a digression, and hope it forms a basis for something...

There is an amazing amount of information that we receive through our five senses. I understand it to be on the order of nearly a terabyte per second. Whatever it is, It is far more than we can consciously process. To use the data, the body operates with thousands of micros running, all the time, while our sensory systems are communicating with each other, without us knowing it. We are rarely aware of the fluid in our inner ear, yet the loop circuitry between it and our entire muscular system provides us with constant equilibrium. It would take a mainframe just to handle that and that is one of many. A developed sense of touch is equally complicated, and feeds us vast amounts of information about the simplest things. The feel of the action is a combination of friction, mass, leverage, and springs. it all comes through the key, so the dynamic behavior of that key is critical and the bushings' contribution is significant.

When the pianist's hand touches a key, before the downward movement begins, there is already a sensory loop beginning, if not already complete. The location of the key is registered in relation to the others, and how definite this registration is depends on where the finger decides that key is located. "Where" can be blurred if the key has sideways movement when the finger touches it. The nervous system of the hand has to subconsciously decide where the middle of that wiggle is. Even though the key is effectively in the same place, if all of them are moving around laterally, the "feel" is one of vagueness. I had an artist tell me that one of our stage pianos felt like he was walking on a tightrope that wasn't tight. This piano wasn't sloppy, but the normal looseness of a working, university, piano, (concerts, warm-ups, accompaniment, Suzuki practice, etc...) was beyond his normal, and he much preferred our other, more coddled piano, with bushings pristine.

Inre tight tolerances creating friction, I think that once there is no compression of the felt by the pins, there is nothing to be gained by further slack. There is no need for there to be any clearance, but it is difficult for us to insure the necessary freedom for repetition without some perceptible movement. Front pins are not always straight, and binding can occur if the bushings are too deep, etc., so we have to have some freedom. It should not be visible, but it should be felt when taking a key and moving it side to side. By the time you can see the key move from a playing position, you have significant wear. Most felt will compact an additional five or six thousandths in the first 10 hours of playing, also, so a new key job needn't start out with any more than the least possible movement.
There are also reasons for resilient, close bushings that have to do with key behavior under staccato playing, (loose keys can bounce uncontrollably at higher speeds).

If you have a brand new bushing job,I don't think it should be loose enough to see keys moving sideways. Saying that a dealership in Japan is doing something as an explanation seems a bit of a stretch. If you can feel looseness in the key when you are playing, it sounds like you didn't get what you were seeking.
Regards,

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#2127856 - 08/04/13 08:34 AM Re: front key bushings regulation [Re: pierrot]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7178
Loc: France
good points, I may add that the way the key is holding on the balance pin is important in the way it is perceived.
A good adjusting of a good condition key shoe allow the "succion" of the key when the front is raised a little, but no motion when the back is raised.

The conical inside of some keys allows for a very long term fit and should not be worked with the usual oval tool, but precisely at a corner in the cone.

That is how we find very old Steiwnay keyboards that have the good fit at balance rail.

The thinner shoes cannot be managed as well.
_________________________
Isaac OLEG - http://picasaweb.google.fr/PianoOleg pro

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#2127899 - 08/04/13 10:56 AM Re: front key bushings regulation [Re: kpembrook]
Minnesota Marty Offline

Platinum Supporter until October 5 2014


Registered: 05/15/12
Posts: 7235
Loc: Rochester MN
Originally Posted By: kpembrook
Personally, I wouldn't stress about it unless you are observing some issue as you play. The purpose of adjusting tolerances is to improve playability -- not to satisfy what somebody has written in a book, even if the book is generally on track

As a pianist, I find this remark to be disturbing. Apparently the OP had work done to correct a problem, or he wouldn't have had the action serviced in the first place. The result of the service was not to done his satisfaction and is merely asking "is this normal?" It is the reason that he submitted his/her question to this forum. His source of reference is irrelevant, as his fingers told him the job had not been well executed and was then given excuses.

A proficient pianist immediately senses a sloppy action. The whys and wherefores of the reasons for the problem should not be the concern of the pianist. That is the job of the technician. If the customer then gets a run-a-round, and tries to obtain additional information as justification for any complaints, that is to be commended. Seeking information and understanding, from multiple sources, does not indicate that the person is a mechanical engineer or a DIYer. It indicates a pianist who wants his/her piano to perform at its maximum capability and is trying to understand why it is not, and obtain validation for apparent displeasure concerning the work which has been performed.
_________________________
Marty in Minnesota

It's much easier to bash a Steinway than it is to play one.

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#2127913 - 08/04/13 11:43 AM Re: front key bushings regulation [Re: pierrot]
Emmery Offline
2000 Post Club Member

Registered: 04/02/08
Posts: 2356
Loc: Niagara Region, On. Canada
Boone's book is excellent as a general guide but you must remember that it concentrates and generally is addressing quality Steinway pianos for the most part. There are some small differences between manufacturing tolerances on the key sizes and the gaps between them, and more importantly, the quality of key bushing cloths. These two things combined may change the "specs" slightly on different brands of pianos. A poor choice in quality of key bushing cloth for eg., will render too much friction if you start to tighten up the tolerance to the level which a high quality piano can be set.

One of the hardest things to do is to develop a consistant way to test lateral movement key to key. I've seen more ways to do this from techs than can be written here but most all use some kind of sideways finger pressure. Myself, I use a dial faced finger type spring gage. I put a small piece of tacky putty on the tip so it gets grip on the key. It looks similar to this, but has a dial indicater as the meter...

Outside of specs, I simply ease up the bushings just enough that friction does not become too heavy or erratic and accept the movement which that combination of pin and cloth gives me, and this will vary a bit amongst pianos. No key should ever move more than 25% of the overall gap between it, and this is very close to Boone's recommendation in most pianos.
_________________________
Piano Technician
George Brown College /85
Niagara Region

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#2127919 - 08/04/13 12:13 PM Re: front key bushings regulation [Re: Minnesota Marty]
kpembrook Offline
1000 Post Club Member

Registered: 04/06/10
Posts: 1294
Loc: Michigan
Originally Posted By: Minnesota Marty
Originally Posted By: kpembrook
Personally, I wouldn't stress about it unless you are observing some issue as you play. The purpose of adjusting tolerances is to improve playability -- not to satisfy what somebody has written in a book, even if the book is generally on track

As a pianist, I find this remark to be disturbing. Apparently the OP had work done to correct a problem, or he wouldn't have had the action serviced in the first place.


Quote:
A proficient pianist immediately senses a sloppy action. The whys and wherefores of the reasons for the problem should not be the concern of the pianist.


My point exactly: If it doesn't feel good then it isn't good. Period. (Which was the thrust of my response)

But OP wasn't saying that, was he? He was citing measurements and specifications -- which, as we both apparently agree -- are subsidiary to the actual feel.
_________________________
Keith Akins, RPT
USA Distributor for Isaac Cadenza hammers and Profundo Bass Strings
Supporting Piano Owners D-I-Y piano tuning and repair

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#2127946 - 08/04/13 01:25 PM Re: front key bushings regulation [Re: pierrot]
Ed Foote Offline
1000 Post Club Member

Registered: 05/03/03
Posts: 1097
Loc: Tennessee
Greetings,
Inre the original op remarks, if a key, black or white, has 1 mm of movement in the bushings, that is way too much for a new job. .012", as per Danny Boone's recommendation, is about maximum for a beginning spec. I have also, in over three decades, never heard or seen any reason that black keys should have more free play than whites.
Regards,

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#2128002 - 08/04/13 03:58 PM Re: front key bushings regulation [Re: Ed Foote]
kpembrook Offline
1000 Post Club Member

Registered: 04/06/10
Posts: 1294
Loc: Michigan
Originally Posted By: Ed Foote
Greetings,

Inre tight tolerances creating friction, I think that once there is no compression of the felt by the pins, there is nothing to be gained by further slack. There is no need for there to be any clearance, but it is difficult for us to insure the necessary freedom for repetition without some perceptible movement. Front pins are not always straight, and binding can occur if the bushings are too deep, etc., so we have to have some freedom. It should not be visible, but it should be felt when taking a key and moving it side to side. By the time you can see the key move from a playing position, you have significant wear. Most felt will compact an additional five or six thousandths in the first 10 hours of playing, also, so a new key job needn't start out with any more than the least possible movement.
There are also reasons for resilient, close bushings that have to do with key behavior under staccato playing, (loose keys can bounce uncontrollably at higher speeds).

If you have a brand new bushing job,I don't think it should be loose enough to see keys moving sideways. Saying that a dealership in Japan is doing something as an explanation seems a bit of a stretch. If you can feel looseness in the key when you are playing, it sounds like you didn't get what you were seeking.
Regards,


I agree that we have complex sensory capabilities that provide huge amounts of useful information about what we are doing. That's why I have said that if it doesn't feel right, then it isn't.

I used to believe the same thing you expressed about if the felt isn't pinching the keypin then it should be OK. It's not. There IS measurable friction with the kind of setup you describe with sideplay 'feelable' but not visible. A bit more side play that is also visible will reduce friction. It may or may not matter much in a given action setup.
_________________________
Keith Akins, RPT
USA Distributor for Isaac Cadenza hammers and Profundo Bass Strings
Supporting Piano Owners D-I-Y piano tuning and repair

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#2128058 - 08/04/13 05:51 PM Re: front key bushings regulation [Re: pierrot]
Tunewerk Offline
Full Member

Registered: 03/26/11
Posts: 405
Loc: Boston, MA
Hello Pierrot!

Key bushing tolerances are usually said to be .007" at spec. What does this tolerance mean?

It's just an important way to communicate that the keys should be firmly held in position by the bushings at the balance rail and front pin. But there's a second, more important function that the front bushings play in an action: the damping mechanism for the keys.

Proper key regulation may vary several thousandths from .007" on different keys to maintain proper dampening friction at the pin. When bushing quality is not at 100%, tradeoffs may need to be made in side-to-side key play to achieve the more important characteristic of damping friction.

The keys should fall back on a noiseless air cushion if they are regulated just right. But the amount of this has to be regulated to other characteristics in the action: most importantly, hammer weight and leverage ratio.

Originally Posted By: pierrot
He explained that recently techs at authorized steinway dealership in japan usually recommend making even more sideways movement.


This may be true because reducing front pin friction is usually the fastest way to decrease downweight on an action. Steinways are notoriously heavy and the Japanese techs may want to be making them respond more like Yamahas (or pre-compensating for humidity expansion).

Good luck and godspeed.


Edited by Tunewerk (08/05/13 12:14 AM)
_________________________
www.tunewerk.com

Unity of tone through applied research.

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#2128059 - 08/04/13 05:55 PM Re: front key bushings regulation [Re: Tunewerk]
ando Online   content
3000 Post Club Member

Registered: 11/23/10
Posts: 3504
Loc: Melbourne, Australia
Really? A noiseless air cushion? That's a new one to me!

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#2128065 - 08/04/13 06:06 PM Re: front key bushings regulation [Re: pierrot]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7178
Loc: France
the only way to use an air cushion is to use polyurethane foam for the front punching, as does a friend to fight impact noise.

I can imagine the sealed mortise, with a little valve yo regulate the harndness , but not.
_________________________
Isaac OLEG - http://picasaweb.google.fr/PianoOleg pro

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#2128224 - 08/04/13 11:14 PM Re: front key bushings regulation [Re: Olek]
ando Online   content
3000 Post Club Member

Registered: 11/23/10
Posts: 3504
Loc: Melbourne, Australia
Yes, that's what I was thinking Isaac. There are too many points of leakage for these bushes to support "air-cushions".

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#2128258 - 08/05/13 12:10 AM Re: front key bushings regulation [Re: ando]
Tunewerk Offline
Full Member

Registered: 03/26/11
Posts: 405
Loc: Boston, MA
I forget how hyper-critical these forums can be at a slight mismanagement of words. 'Air cushion' was a descriptive device as to the feeling of well regulated keys.

You are right, Ando - what is happening in the key is just the right amount of felt contact with the front pin that gives that feel of cushioned dampening.
_________________________
www.tunewerk.com

Unity of tone through applied research.

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#2128317 - 08/05/13 02:44 AM Re: front key bushings regulation [Re: Tunewerk]
ando Online   content
3000 Post Club Member

Registered: 11/23/10
Posts: 3504
Loc: Melbourne, Australia
Originally Posted By: Tunewerk
I forget how hyper-critical these forums can be at a slight mismanagement of words. 'Air cushion' was a descriptive device as to the feeling of well regulated keys.

You are right, Ando - what is happening in the key is just the right amount of felt contact with the front pin that gives that feel of cushioned dampening.


Thanks for the clarification. I certainly wasn't being snide in my reply - I honestly thought you meant it literally. No offence intended.

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#2128328 - 08/05/13 03:23 AM Re: front key bushings regulation [Re: pierrot]
phacke Offline

Gold Supporter until November 11 2014


Registered: 10/18/12
Posts: 465
Loc: CO, USA
Hello pierrot,
Possibly, the bushing felts were changed and you got whatever the new felt/cloth, glue, minus (but hopefully not) whatever wood fiber came off in the change out. How do the key spacings look? Do the keys ever touch with the excess side-to-side motion? Do the keys move enough so that the spacing of the keys may look different from time to time, depending on how you played the keys last?

I would wonder what the pros would recommend as to mitigation if pierrot decides to request reduction in side to side motion. My vague recollection Reblitz says to swell the wood if there is too much play and not turn the metal front pins because that causes excess localized wear on the felt/cloth bushings, but I think most techs turn the metal pins.

Regards-
_________________________
phacke

Steinway YM (1933)
...Working on:
G. F. Händel: Suite in G minor (HWV 452)
J. S. Bach, Sonata No. 1 in B minor (BWV 1014) duet with violin

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#2128331 - 08/05/13 03:47 AM Re: front key bushings regulation [Re: pierrot]
bkw58 Offline

Silver Supporter until December 19, 2014


Registered: 03/14/09
Posts: 1623
Loc: Conway, AR USA
There is a good reason why front key pins are designed in a certain way. Turning these to reduce "play" is not a good idea.
_________________________
Bob W.
Retired piano technician
Piano Technicæ

"Not to know what took place before you were born is to remain forever a child." - Cicero

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#2128859 - 08/06/13 09:17 AM Re: front key bushings regulation [Re: pierrot]
pierrot Offline
Junior Member

Registered: 06/20/07
Posts: 19
Loc: japan
first, to add further informations...

the piano is yamaha c3, bushing cloth from renner germany(i suppose it is of high quality?),and the room humidity/temperature is well-controlled all year round(thus no need for pre compensating for humidity expansion).
keypins polished before rebushing.
and, no, i am not an engineer, a sirious pianist.

yes, now the keys feel "better" that's for sure.
before rebushing, cloths were quite worn,dented, if not totally worn out, so thats no wonder(that keys now feel better).
but the thing is, i wanted my bushings starting out close to ideal as possible, and having read mr boone's book
several times, i supposed his regulation guideline to be reliable(to be ideal).

i told him about this beforehand, yet he had done things the way i described in the first post. plus he regulated about an octave and a half of both extreams of keyboard's bushings looser than the rest, because , he says, they wear slower than the rest(center).
i thought this meant that he thought those looser ones are the norm.
so "is there anything wrong with keys that moves side ways barely visible?"
"does anyone have any objections to boone's recommendations?"

to be continued..
_________________________
pardon me for asking......too much?

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#2128863 - 08/06/13 09:25 AM Re: front key bushings regulation [Re: pierrot]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7178
Loc: France
what thickness are the cloths ? they are somewhat thick for Yamahas. 1.35 if memory serves. Nikke cloth, from Japan , is very good.

the side play should not be noticed really.

too much play at the balance is enough to give a less good impression, because the balance is important for the equilibrium of the hand/fingers.
If you have some "baby foot motion" really perceived, there is too much play.

depending of the springiness of the cloth more or less side play allowed. the Japanese cloth is more springy, German cloth more firm.

using too much glue can tighten the cloth and make it thinner.

ungluing the original cloth, glued with PVA glue, is not so easy. an option is to cut in the glue joint. if moisture is used a lot is necessary and as the wood is soft it is too easy to take out some wood with the old cloth.

regulating the sideplay before everything is well dry (a few days depending of the weather) is also giving too much play.

you may check the play at rest and with the key bottoming. The Yamaha tool open more the aperture tan the bottom, making a different play in the 2 positions.

Pliers are better.

As it is a soft wood the mortise can be closed by tapping on the wood.


Edited by Olek (08/06/13 09:37 AM)
_________________________
Isaac OLEG - http://picasaweb.google.fr/PianoOleg pro

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#2128867 - 08/06/13 09:39 AM Re: front key bushings regulation [Re: pierrot]
Johnkie Offline
500 Post Club Member

Registered: 06/04/11
Posts: 688
Loc: England
There should be a tiny amount of sideways play when the key is at the bottom of its travel. The amount of play should be felt usings the lightest of sideways presure, not yanking it from side to side. Remember these are guide pins, and are not meant to increase friction having the pins in constant contact with the bushing cloth.
_________________________
Concert Tuner & Technician for the past 49 years in the United Kingdom
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#2128869 - 08/06/13 09:41 AM Re: front key bushings regulation [Re: pierrot]
pierrot Offline
Junior Member

Registered: 06/20/07
Posts: 19
Loc: japan
1.3mm. 1.35mm is the pre-cut one . he used the wide sheet of cloth that one has to tear by hands.

by the way, how do you check the proper fit of the balance bushings? is there any way of checking them exclusively, so one knows if its balanse or front thats not right?

lol what the heck is "baby foot motion"?


Edited by pierrot (08/06/13 09:43 AM)
_________________________
pardon me for asking......too much?

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#2128870 - 08/06/13 09:47 AM Re: front key bushings regulation [Re: pierrot]
Ed Foote Offline
1000 Post Club Member

Registered: 05/03/03
Posts: 1097
Loc: Tennessee
Greetings
I check the balance rail bushing by lightly touch the front of the key and watching the back check. If the backcheck will not sway from side to side while I rub sideways on the key top, the bushing is too tight. A light touch, and an almost imperceptible back and forth at the check will tell me what I need to know.
I have never heard of leaving different parts of the keyboard bushing looser in expectation of wear. This guy sounds like a hot-air artist...
Regards,

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#2128879 - 08/06/13 10:14 AM Re: front key bushings regulation [Re: pierrot]
pierrot Offline
Junior Member

Registered: 06/20/07
Posts: 19
Loc: japan
i am very glad that now i am getting informations from slightly different angles.

especialy mr foote, i always have enjoyed reading your insightfull, logical, educational posts here and ptg archives for quite a long time.

and marty, you seemed to be reading my mind!
my yamaha might lack depth in tone, but i just want to bring
the action to the optimum condition, at least , for a while.
_________________________
pardon me for asking......too much?

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#2128881 - 08/06/13 10:17 AM Re: front key bushings regulation [Re: pierrot]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7178
Loc: France
nice tip, Ed,

You also can insert a 0.2 mm blade on the side of the pin and feel how it is tight.

IF 0.05 mm miss on the cloth , that makes 0.1 mm for one mortise, enough to feel something a little sloopy (not much, but enough to be perceived).

But bushing cloth thickness is not as precise, and will depend on air moisture somewhat I had 1.30 that was measured at 1.25 and 1.35 that measured 1.4 (when measured with the good tool)

Pierrot, sorry, "baby foot" is a French name for :
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#2128882 - 08/06/13 10:22 AM Re: front key bushings regulation [Re: pierrot]
Olek Online   content
7000 Post Club Member

Registered: 03/14/08
Posts: 7178
Loc: France
Originally Posted By: pierrot

yes, now the keys feel "better" that's for sure.
before rebushing, cloths were quite worn,dented, if not totally worn out, so thats no wonder(that keys now feel better).
but the thing is, i wanted my bushings starting out close to ideal as possible, and having read mr boone's book
several times, i supposed his regulation guideline to be reliable(to be ideal).



What count is not some theoretical measure , even if the usual numbers are good, but what you perceive under the fingers.

If the keys where worn, the backchecks may be less efficient today ( alittle worn out) , but also the hammer flanges are probably very loose, so as long as the keyboard is stable under the fingers all is well, you will not have further "straightening" of the touch without other options, pinning, correction of worn leathers/cloths, good damper timing.

If you keys have "pulley" (front to back) this is enough to loose some of the benefit of new bushing cloths.

Can be closed somewhat by moistening the wood with 70% alcohol.
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Isaac OLEG - http://picasaweb.google.fr/PianoOleg pro

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#2128947 - 08/06/13 01:13 PM Re: front key bushings regulation [Re: pierrot]
Bill McKaig,RPT Offline
Full Member

Registered: 05/16/11
Posts: 86
Loc: Tampa, FL
Yamaha keys are very accurately made. There is no reason your bushings shouldn't be perfect.

Find a new Yamaha grand and feel the keys. Your keys should feel the same.
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#2129260 - 08/07/13 02:21 AM Re: front key bushings regulation [Re: kpembrook]
pierrot Offline
Junior Member

Registered: 06/20/07
Posts: 19
Loc: japan
Originally Posted By: kpembrook
Originally Posted By: Ed Foote
Greetings,

Inre tight tolerances creating friction, I think that once there is no compression of the felt by the pins, there is nothing to be gained by further slack. There is no need for there to be any clearance, but it is difficult for us to insure the necessary freedom for repetition without some perceptible movement. Front pins are not always straight, and binding can occur if the bushings are too deep, etc., so we have to have some freedom. It should not be visible, but it should be felt when taking a key and moving it side to side. By the time you can see the key move from a playing position, you have significant wear. Most felt will compact an additional five or six thousandths in the first 10 hours of playing, also, so a new key job needn't start out with any more than the least possible movement.
There are also reasons for resilient, close bushings that have to do with key behavior under staccato playing, (loose keys can bounce uncontrollably at higher speeds).

If you have a brand new bushing job,I don't think it should be loose enough to see keys moving sideways. Saying that a dealership in Japan is doing something as an explanation seems a bit of a stretch. If you can feel looseness in the key when you are playing, it sounds like you didn't get what you were seeking.
Regards,




I used to believe the same thing you expressed about if the felt isn't pinching the keypin then it should be OK. It's not. There IS measurable friction with the kind of setup you describe with sideplay 'feelable' but not visible. A bit more side play that is also visible will reduce friction. It may or may not matter much in a given action setup.



mmmmmm, i would love to listen to further discussion two of you would have about this...
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