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Leveled keys too high

  • 1.  Leveled keys too high

    Member
    Posted 05-11-2022 13:28
    Here's a big oops has just occurred.
    It's common to level keys a smidge higher than they were before leveling, because (a) it's easier and faster to add balance-rail punchings than to remove them, and (b) the full-keyboard straight-edge works best when you can see the gaps, i.e. when the straight-edge lies slightly above the level of most or all the intervening keys. So we block up keys 1 and 88, rest a straight-edge on the end keys, and proceed to raise all the intervening keys to the newly correct height.
    Which (on a grand) slightly affects hammer height, because raising the key also raises the capstan a tiny bit. On a vertical, it affects lost motion. That's why we level keys before setting blow.
    So on this Yamaha C3 grand, I raised the key height and proceeded to do a full regulation at my shop, then returned the action to its piano a couple of days ago, and everything works beautifully, letoff is exactly right, aftertouch is perfect, and the tuning was great. I explained to the client what work I had done, put the piano back together and left happy.
    Only to get the following email that night:
    "Nice seeing today and thank you for your beautiful work - the piano sounds great! One, hopefully minor, problem - we noticed that when closing or opening the fall-board on the keyboard, it pushes all the keys down, making the keys uneven and very shallow. Can you please take a look at that when you come to tune the other piano? It did not happen before, probably since the keys were all a little lower."
    In my initial measurements, I had neglected to check fallboard clearance. Now I have to fix that, at no cost to the client. Note to self: Don't make that mistake again.
    I don't know how much clearance is needed. Easiest option would be to replace the fallboard felt with something thinner, if that would suffice. More likely I will have to re-level the keys, both naturals and sharps. Maybe replacing the balance rail felt punchings with thinner ones would do the trick, or maybe just removing x or y paper punchings, but of course after any such gang replacement, a fine-tuning of the level will be necessary.
    It will be at least four or five days before I go back to fix this.
    What would you do?

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    Jason Kanter
    Lynnwood WA
    425-830-1561
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  • 2.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-11-2022 14:19
    Jason,

    How much lower do the keys need to be? 1/4 mm? 1/2mm? More?

    Is there any latitude in the bedding of the balance rail? If the glide bolts are adjusted to have more than contact plus .001"-.003", you may have some room to move key height down globally in just a few minutes without messing with the punchings.

    As I have posted to this list previously, when we level keys, we remove the hammer action (AKA top stack) so that we can consolidate the number of punchings (using a spring/pressure gauge, on the paper punchings only), and arrange them in order from small to large, top to bottom. (BTW, using this approach helps avoid unintentional key height creep.)

    There is a roughly 2:1 ratio between the thickness of a balance rail punching and the change at the front of the key. So if, for example you needed to lower the level by 1/2 mm (~.020"), you could make each stack of punchings 1/4 mm (~.010") shorter. If you happen to have punchings on the action that equal the reduction you seek, you could simply remove one of them from each note. Otherwise, you could spend a moment with the spring/pressure gauge to modify the height of the stacks of punchings as needed.

    It has probably already occurred to you that, in addition to hammer blow distant being affected, any change in key height will require accomodation in key dip to maintain that even aftertouch.

    Good luck, and let us know how this turns out!

    Alan

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    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
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  • 3.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-11-2022 16:03
    I'm betting ($1.00) that the keyboard does not need to be releveled. Maybe thinner cloth but also possible that there's excess 'lip' of cloth catching the back edge of the naturals. This would be even more likely if keytops had been replaced with thick plastic. Once the felt initially catches, it's likely to curl and take on even more dimension.  I'm betting on the lip.

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    David Skolnik [RPT]
    Hastings-on-Hudson NY
    917-589-2625
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  • 4.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-11-2022 17:10
    I'm with David on this. If you only raised things a "smidge" I highly doubt it would create this problem. More likely something else.

    Peter Grey Piano Doctor

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    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
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  • 5.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-12-2022 09:53
    This is one of the many things I learned the hard way. The fallboard felt did catch and fold, but they were still a smidge to high even after fixing that. I had to lower & fix keydip. I have a question for Alan. Please forgive my ignorance, but what is, "a spring/pressure gauge" that you use "on the paper punchings only"? Thanks. 

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    Maggie Jusiel, RPT
    Athens, WV
    (304)952-8615
    mags@timandmaggie.net
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  • 6.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-12-2022 10:17
    Maggie,

    A dial spring gauge or dial pressure gauge is spring loaded, so it applies the same amount of pressure for each measurement. This is necessary when measuring compressible materials, such as a pile of paper punchings, or leather, felt, cloth and the like.

    For key leveling, we first take a reading of which keys are higher than target and which are lower, and make a guesstimate as to by how much they are off. Then we reconstitute the piles of paper punchings on each key to achieve the desired changes, using as few punchings as possible. Doing this, of course, requires repeatedly removing the top stack/hammer action (which we do with cordless screwdrivers and six inch bits).

    Clear as mud?

    Alan

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    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
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  • 7.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-12-2022 00:27

    A revisit to the piano is needed. There needs to be some "lift" to the keys to avoid that. If there is inadequate clearance then I'd bite the bullet and lower the key height which means you'll have to reset dip too. 


    i always measure fall board clearance on action jobs. Been burned on this before. 



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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 8.  RE: Leveled keys too high

    Posted 05-13-2022 08:31
    This may be a stupid suggestion but is there any space at all above the fallboard and stretcher? If it's not a slow close fallboard, might it be easier to reposition the fallboard a little higher by repositioning the pivots? 






  • 9.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-12-2022 02:05
    The basis of all piano regulation should start with key height, and that depends on the fallboard.  Every other adjustment needs to "hinge" on key height, then dip.

    I have seen countless pianos regulated with excess key height (done a few myself).  Generally, the key fronts are usually square when properly regulated. Start with key height, then dip, then everything else should follow.

    But then every piano is different.

    Just my humble opinion....

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    Blaine Hebert
    Duarte CA
    626-795-5170
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  • 10.  RE: Leveled keys too high

    Member
    Posted 05-12-2022 07:09
    Check the height of the white keys above the key slip. Insure that the front rail pins are at least ¼" (8 mm) up into the bushings, check the sharps too. Chances are the OEM felt is not too thick. How do the keysticks fit below the upstop rail without shims on the ends. Did you bed the keyframe before leveling? Spec height is 65.5 mm. 12 mm on the sharps.

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    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
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  • 11.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-13-2022 07:55
    Jason,

    Have you considered adding a thin shim under the back rail cloth.
    Doing so would lower the front of the keys to where they were before you leveled them.

    You would of course need to adjust the hammer blow and keydip to accommodate, but
    this seems the best way to get it dialed back in properly with the least amount of additional work.
    Letoff would not be affected and changes to drop would be negligible.

    Yamaha keyframes are a softwood, so you probably have it set where it should be and
    trying to fudge it may result in problems with changes in humidity as softwoods react
    more readily than hardwoods like maple or poplar.

    Hope this helps.

    Dave


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    Dave Conte

    University of Tennessee
    Knoxville TN
    817-307-5656
    Owner: Rocky Top Piano
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  • 12.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-13-2022 08:30
    Hey Jason,

    You might want to check the brackets that hold up the fallboard, they can wear or lower with age.  I have seen a small piece of leather put between the pin and the rest spot to give a smidge of clearance.

    Good luck, let us know what you do to fix the problem.

    Gina

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    Gina Bonfietti
    Milford CT
    203-882-8082
    gina@ginaspiano.com
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  • 13.  RE: Leveled keys too high

    Member
    Posted 05-13-2022 09:05
    The consequence of raising the back rail is that the dampers are now going to lift too soon, plus the sostenuto will need readjusting.
    Shimming he fallboard is all well and good as long as it clears the stretcher when closed.

    Set the key height to spec. Don't complicate things any more than they already are. Chalk it up to experience.
    "Experience, knowledge and wisdom are gained thru bad decisions."

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    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
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  • 14.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-14-2022 09:33
    Interestingly (or not), when Googling: "Experience, knowledge and wisdom are gained thru bad decisions.", the only citation that comes up is the above discussion, which doesn't make it any less valid, as a source of aphoristic pause (as in "hmm"!?).  Even it were to have originated as a fortune cookie prize, its thought value remains undiminished, however, the more sobering reality is that, for many of us, knowledge and (especially) wisdom do not follow, as a matter of course.  Some of us just revel in wallowing in bad decisions.

    Meanwhile, anticipation grows for the sequal: Return to the Leveled Keys Too High.
    And thanks, Jon, for the specificity of your responses.


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    David Skolnik [RPT]
    Hastings-on-Hudson NY
    917-589-2625
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  • 15.  RE: Leveled keys too high

    Member
    Posted 05-14-2022 13:33

    At my request, Client sent me this photo of the fallboard felt on the keys. It's quite thick and I believe I will be able simply to replace with thin fallboard felt. I'll see it in a week or so; meanwhile they use the piano minus fallboard  .



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    Jason Kanter
    Lynnwood WA
    425-830-1561
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  • 16.  RE: Leveled keys too high

    Registered Piano Technician
    Posted 05-14-2022 14:02
    Jason,

    Are those the original keytops or were they replaced previously by someone? (I don't recall if you specified this or not).

    Peter Grey Piano Doctor

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    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
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  • 17.  RE: Leveled keys too high