Pianotech

  • 1.  Inertia Touch Wave Preview

    Posted 01-08-2023 10:40

    Hi All,
    Here's a little preview of something I've been working on, and am quite proud of it.
    I've been working on a new software for key balancing. I call it Inertia Touch Wave. My goal was to make it as simple as possible, and at the same time make it effective. After about a year of trial and error i finally have settled on what has become a pretty cool system. It uses a different way to measure – function of the whole rather than the individual parts.


    I have eliminated these measurements-
    1)action ratio
    2)measuring all parts independently
    3)Front Weight 

    and replaced them with what I think is more accurate:
    1) FKL  (Front Key Length)
    2) Inertia
    3) Keyweight

    Overall, there is less measurements to take than in other systems I have looked at.

    I like keyweight better than front weight because when you start with a targeted gram weight the proper placement of lead in the key solves itself to arrive at a specific Downweight.

    The inertia measurement turned out to be a key element,   it is what I like to call the "conductor for the orchestra" because it tells you when all of the other elements (DW,UW,F, All Mass, and leverage) are working in harmony with each other.

    The software is finished, and I am currently working on a User Manual. After I use it on a few more actions, and with feedback from some fine pianists I know, i'll hopefully get it released sooner rather than later.

    Shout out to Dale Erwin who helped choose the name over the others I had.

    Here's the first reaction of the first action with the inertia balanced. https://www.youtube.com/watch?v=6zSlMpYM04k

    Here is a screen shot of the main interface.

    screenshot of software
    -chris


    ------------------------------
    Chernobieff Piano Restorations
    "Where Tone is Key, and Mammoths are not extinct."
    865-986-7720 (text only please)
    ------------------------------


  • 2.  RE: Inertia Touch Wave Preview

    Registered Piano Technician
    Posted 01-11-2023 11:47
    How are you measuring inertia, Chris?

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    John Pope
    University of Kentucky School of Music
    Lexington, KY
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  • 3.  RE: Inertia Touch Wave Preview

    Posted 01-11-2023 19:45
    The formula for inertia is Mass times Radius squared. But there are many variants based on many factors. Without going into the weeds of formulas on this forum, I ended having to calculate a variant for the piano action as none existed that weren't calculus based. And calculus is not my cup of tea. My calculations are based on some of the experiments i did, some of which are on my youtube channel. The accelerated action vs regular actions is particularly interesting. A recent revelation since recording inertia values is you can have SW,FW,DW, and Friction smooth and even, but it doesn't mean inertia is. So its another level of refinement.

    -chris

    ------------------------------
    Chernobieff Piano Restorations
    "Where Tone is Key, and Mammoths are not extinct."
    865-986-7720 (text only please)
    ------------------------------



  • 4.  RE: Inertia Touch Wave Preview

    Registered Piano Technician
    Posted 01-11-2023 20:06
    I subscribe to your YouTube channel and have noticed a lot about inertia lately.  😁  First, congratulations on this project!  Second, I'll be starting a total refurbishing job on my Knabe model  C action in the next couple months and I'm very interested in learning more about this (this is my first time doing this job).  The key leads are corroded and the initial touch weight wasn't to my liking anyway (I play professionally).  Please keep us updated on this project!

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    Tim Foster
    New Oxford PA
    (470) 231-6074
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  • 5.  RE: Inertia Touch Wave Preview

    Posted 01-17-2023 15:36
    Hi Chris, I have not attempted to calculate inertia but have assumed an even SW, DW curve with all else being equal would result in a smooth inertia curve.
    In response to your comment " A recent revelation since recording inertia values is you can have SW,FW,DW, and Friction smooth and even, but it doesn't mean inertia is" I can't get my head around this unless you are referring to different key leading resulting in the same FW.   W x A = M, M / W = A, M / A = W. So much lead near the balance pin will yield the same FW as less lead at the front. The heavy leaded key with lead near the balance pin will have less inertia than the lightly lead front weighted key. Is this to what you refer?  Also, are you saying friction affect inertia. 
    Respectfully, Fenton

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    Fenton Murray, RPT

    Fenton
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  • 6.  RE: Inertia Touch Wave Preview

    Posted 01-17-2023 19:52
    Yes, that is the assumption everyone else makes too. But, i'm charting it out as i don't like to assume. For example, in my chart above you can clearly see the sharps and naturals even have different inertia values from each other. It seems to me you are confusing force with inertia as you are quoting the F=MxA formula.
    You said- "So much lead near the balance pin will yield the same FW as less lead at the front". 
    ME:This is True! But this also shows why FW is a terrible value to go by.
    You- "The heavy leaded key with lead near the balance pin will have less inertia than the lightly lead front weighted key."
    Me: Wrong. Zero means no inertia, therefore the higher the number the more inertia there is.

    Inertia (MxR^2is the property of an object to resist a force. See why the force formula doesn't apply?

    So with a piano key, which the radius stays about the same but the mass changes. So a lot of mass near the balance increases its resistance because your adding mass.
    Here's proof- https://www.youtube.com/watch?v=f-7-K1462-Y&t=31s

    Using the same mass, but changing the radius -one near the axis, the other far from the axis.
    https://www.youtube.com/watch?v=7PRZ5IIT5Tg

    Hope that helps.
    -chris


    ------------------------------
    Chernobieff Piano Restorations
    "Where Tone is Key, and Mammoths are not extinct."
    865-986-7720 (text only please)
    ------------------------------