Kawai KG6C Bass String Breakage Problem

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Regi Hedahl

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May 19, 2021, 11:14:10 PM5/19/21
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Total Insanity! No wonder this Kawai KG6C was breaking bass strings left and right! I measured them up and inserted the data into Typogramen and some of the strings have a Stress % of over 100%. I have come up with a rescale that is far more reasonable and will probably sound more pleasant. Most bass string winders won't go over anything over 75%. Next time a bass string breaks on you (for seemingly no reason), measure it up before assuming anything.
Regi

Untitled 1-001.jpg

Joe Garrett

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May 20, 2021, 3:33:49 AM5/20/21
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Hmm? Good advice. However, I'm not real keen on the program you used. Not enough perameters imo. In the steel column what does "M" stand for? Will that program convert to Machinist's Inch measurments and normal U.S. of  A lingo? Hate Metric! I've never seen a bass scale with so many problems as that one. I'd run that past Don Mannino and see what he says about it. Just can't imagine that getting past the inspectors and many engineers of a good company like Kawai. Just doesn't compute in my soft grey matter. They do tend to push the envelope sometimes, but I'm thinking something stinks in Sweden and it's not the Lutefisk from their neighbors.<G> For one thing any string over 80 % would likely break chipping it up to pitch upon installation. Over that, you wouldn't even get it close to pitch. Again, something is amiss and stinks. Suspect the strings were replaced before you got to the turd!<G>
Best,
Joe

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Squares R I
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Regi Hedahl

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May 20, 2021, 9:02:19 AM5/20/21
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Joe,

The program I used came from Paulello's website.  It can be downloaded free of charge from
 http://www.stephenpaulello.com/en/typogramme

Paulello sells 5 types of wires with different tensile strengths.  Type "M" wire is one of the wires sold and its tensile strength is very similar to Mapes or Roslau piano wire.  The programs purpose is to help piano technicians choose a wire that keeps the % stress in the goldilocks zone.  An example would be a Steinway B.  The program would most likely suggest the use of Type "O" wire for the lowest "honky sounding" tenor plain string wires.  Type "O" wire has lower tensile strength than normal wire and substituting that wire would increase the % stress.

The program uses only metric unfortunately for us Americans.

Regi

Joe Garrett

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May 20, 2021, 1:00:37 PM5/20/21
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Regi,
I'm tempted to run your numbers on Scale Master, (my and friend's scale program that will do both kinds of numbers). Then, perhaps, I can make heads or tails out of the numbers you have derived from that program. The numbers are just not correct imho. Perhaps a misadjusted program or not set for the perameters or something. The numbers just don't add up in my mind. I'll get back to you.
Best,
Joe

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From: Regi Hedahl
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Regi Hedahl

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May 20, 2021, 2:34:56 PM5/20/21
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Joe,

Attached are the numbers in a much friendlier format.  

Regi
Kawai KG-6C - Original.xls

Joe Garrett

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May 20, 2021, 3:50:21 PM5/20/21
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"friendlier"?! NOT! It's still metric, which my 82 year old brain does not accept.<G> Since there is no legend to tell me what the various colums are, it makes no sense to me.
I'll run the numbers in English Machinist if you don't mind.
One thing about the "metric" thang: we run the numbers in the program which spits out pounds, (english), of tension! What the heck is that? If one is to embrace metric, then kick the final numbers out in metric! Sheesh! Hate that.
Best,
Joe

-----Original Message-----
From: Regi Hedahl
Sent: May 20, 2021 11:34 AM
To: pianotech
Subject: Re: [pianotech] Kawai KG6C Bass String Breakage Problem

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Regi Hedahl

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May 20, 2021, 4:12:23 PM5/20/21
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Joe,

Here it is again but I removed the metric stuff and added an additional legend.

-Regi
Kawai KG-6C - Original.xls

Stephen Powell

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May 20, 2021, 8:52:00 PM5/20/21
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Hi Regi,

 

I ran the numbers on notes 1, 11, 22 in Pscale and came up with break percntages of 35%, 74%, 83% respectively.  I think the cores in the higher part of the bass are too light for this scale.  FWIW I have been designing bass scales and making strings for 25 years.  Years ago I did some math with a mechanical engineer using the specs from the Roslau factory for break %.  We found Pscale to be so close as to not be worth quibbling about.  However – and I know that the Paulello typogram uses break % differently – I couldn’t get the typogram to make sense for me with regards to break %.  I don’t wind strings above about 65% (Pscale).

 

Hope this helps!

Regards,

Stephen (RPT/ARPT)

 

 

 

Sent from Mail for Windows 10

 

From: Regi Hedahl
Sent: Thursday, 20 May 2021 3:14 PM
To: pianotech

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Joe Garrett

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May 20, 2021, 11:16:23 PM5/20/21
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Regi,
One thing I've learned about Kawai in the last few years: they like high tension scales and a bit higher numbers in touch. Not sure why, but that's them.
What I found with a quickie evaluation as given, is that they went to too small of a core/wrap in notes 17 through 24, which put them in the 70% and above in breaking strength. The rest of the scale hovers around 60% or lower, so no problem there imo. Hope that helps clarify. BTW, the transition between notes 26 and 27, (wound to plain) could be improved imo. (Over-all tension of the bi-chords combined to the over-all tension of the tri-chord plain wire combined should be within 20% imo.)
Best,
Joe

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From: Regi Hedahl
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Joe Garrett

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May 20, 2021, 11:21:59 PM5/20/21
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Hmm? I'm using Scale Master, which bases it's calculation on Dr. Sanderson's work, for the most part. I'm getting way different numbers than you. PScale needs to be upgraded imo or else my 'puter is lying!<G> (I have PScale, but quit using it years ago, for this type of problem.)
I agree that anything over 65% is TOO MUCH! (Example: M&H A0 at around 75%+ depending on who/what placed the bridges.)

Best,
Joe

-----Original Message-----
From: Stephen Powell
Sent: May 20, 2021 5:51 PM
To: "pian...@googlegroups.com"
Subject: RE: [pianotech] Kawai KG6C Bass String Breakage Problem

Hi Regi,

 

I ran the numbers on notes 1, 11, 22 in Pscale and came up with break percntages of 35%, 74%, 83% respectively.  I think the cores in the higher part of the bass are too light for this scale.  FWIW I have been designing bass scales and making strings for 25 years.  Years ago I did some math with a mechanical engineer using the specs from the Roslau factory for break %.  We found Pscale to be so close as to not be worth quibbling about.  However – and I know that the Paulello typogram uses break % differently – I couldn’t get the typogram to make sense for me with regards to break %.  I don’t wind strings above about 65% (Pscale).

 

Hope this helps!

Regards,

Stephen (RPT/ARPT)

 

 

 

Sent from Mail for Windows 10

 

From: Regi Hedahl
Sent: Thursday, 20 May 2021 3:14 PM
To: pianotech
Subject: [pianotech] Kawai KG6C Bass String Breakage Problem

 

Total Insanity! No wonder this Kawai KG6C was breaking bass strings left and right! I measured them up and inserted the data into Typogramen and some of the strings have a Stress % of over 100%. I have come up with a rescale that is far more reasonable and will probably sound more pleasant. Most bass string winders won't go over anything over 75%. Next time a bass string breaks on you (for seemingly no reason), measure it up before assuming anything.

Regi

 

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Stephen Powell

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May 21, 2021, 12:04:54 AM5/21/21
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Joe,

 

As I said, I’ve crunched the numbers based on the Roslau specs (which is very close to Paulello type “M”) and I therefore have every reason to trust the numbers that I’m getting from Pscale.  As it happens, Tremaine Parsons has devoted a lot of time upgrading Pscale over the last several years.  Where can I try this “Scale Master” of which I can find no reference to with internet searches???

 

Stephen

 

Sent from Mail for Windows 10

 

Al Guecia/Allied PianoCraft

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Jun 29, 2021, 3:30:11 PM6/29/21
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Fellow piano techs and Joe G,

All the phone numbers I have for Young Chang are no longer in service. I have 3 questions. Does anyone know the price of them now? Does anyone have a working phone number for Young Chang? Are they still available?

Thanks,

Al -
High Point, NC

Joe Garrett

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Jun 29, 2021, 4:23:33 PM6/29/21
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No Clue on all counts. I have never installed the action brackets. Hoping my luck holds.<G>


Best,


Joe


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From: <pian...@googlegroups.com>
Sent: Jun 29, 2021 12:30 PM
To: Pianotech Google <pian...@googlegroups.com>
Subject: [pianotech] Young Chang action brackets


Fellow piano techs and Joe G, All the phone numbers I have for Young Chang are no longer in service. I have 3 questions. Does anyone know the price of them now? Does anyone have a working phone number for Young Chang? Are they still available? Thanks, Al - High Point, NC -- You received this message because you are subscribed to the Google Groups "pianotech" group. To unsubscribe from this group and stop receiving emails from it, send an email to pianotech+...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/pianotech/041142B2-7C45-4CC5-B9EC-72BC7E0E4EC3%40outlook.com.

Joe Garrett

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Jun 29, 2021, 4:23:47 PM6/29/21
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Krystal Zhang

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Jun 29, 2021, 4:27:50 PM6/29/21
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I had them replaced about two years ago. I contacted Vincent and don’t recAll how much I paid, maybe around $350 us?

Vincent Choi

10541 Calle Lee STE 119
Los Alamitos, CA 90720
Phone: 657-233-1888/714-699-1818
Fax: 714 509 1119
Email: vince...@pal-sound.com

Best Regards

> On Jun 29, 2021, at 4:23 PM, Joe Garrett <joega...@earthlink.net> wrote:
>
> No Clue on all counts. I have never installed the action brackets. Hoping my luck holds.<G>
> To view this discussion on the web visit https://groups.google.com/d/msgid/pianotech/437066e8-93ec-f111-ca33-566094c2ba65%40earthlink.net.

Allied PianoCraft

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Jun 29, 2021, 4:55:35 PM6/29/21
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Thanks Krystal.

High Point, NC
Al -


On Jun 29, 2021, at 4:27 PM, Krystal Zhang <hiza...@gmail.com> wrote:

I had them replaced about two years ago. I contacted Vincent and don’t recAll how much I paid, maybe around $350 us?
To view this discussion on the web visit https://groups.google.com/d/msgid/pianotech/6AA431F4-2D47-479D-B626-6FA08029E405%40gmail.com.

Don

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Jun 29, 2021, 6:14:44 PM6/29/21
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Hi Al,

From facebook:

Did you call Vincent Choi? 657-233-1888
vince...@pal-sound.com. If not him, Mark Purney was supposed to be working on making them on his 3Dprinter.

Mark Purney
I believe Vincent has them in stock again, unless something changed in the last few days.
We made a few sets and still have a small handful left in stock, but we don’t plan on making more unless the OEM brackets become unavailable again.



Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.P.T.
Non calor sed umor est qui nobis incommodat
mailto:pian...@yahoo.com http://www.donrose.ca/
Box 37181, Regina, SK S4S 7K4
306-539-0716


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William Monroe

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Jun 29, 2021, 6:22:27 PM6/29/21
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Go to the support page of Young Chang USA. They prefer things be done online, it seems. I think I paid $55 for my last set (last year).

http://youngchang.com/downloads/

William R. Monroe, RPT



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Allied PianoCraft

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Jun 29, 2021, 10:33:31 PM6/29/21
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Thanks everyone. Very helpful information. Vincent responded quickly via the internet. They are in stock.


High Point, NC
Al -


On Jun 29, 2021, at 6:22 PM, William Monroe <bi...@a440piano.net> wrote:



Joe Garrett

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Jun 30, 2021, 2:00:31 AM6/30/21
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I'm curious, ...how much per set?

Best,

Joe

Allied PianoCraft

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Jun 30, 2021, 6:29:09 AM6/30/21
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$100, includes shipping.


High Point, NC
Al -


On Jun 30, 2021, at 2:00 AM, Joe Garrett <joega...@earthlink.net> wrote:


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