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Bending let off dowel screws

  • 1.  Bending let off dowel screws

    Registered Piano Technician
    Posted 03-17-2023 14:33

    Hello,

    I recently put on new hammers with new shanks and flanges on a Cline grand piano, possibly made in Korea in the 80s.  It originally had a digital player system that was taken out.  Anyway, it has Yamaha type aluminum action rails and the screws for the let off dowels are connected to the aluminum rail.  I noticed before I regulated the new parts that the jack tenders were touching really close to the back of the let off dowel felt.  After regulation it seemed to get worse, until a hard blow blow on some low bass notes made the hammers block on the strings because the tender just slipped past the let off dowel completely.  I screwed the let off dowel up so that it was well supported on the screw and just bent the screw backwards by pressing with my thumb.  I feel funny about doing this because it makes me think I may have done something wrong in the regulation for the let off dowels to be so out of place from the jack tenders. But it plays really well otherwise.

    I'd like to bend all of these let off screws but am concerned that they might break.  Has anyone ever done this?

     

    just wondering 



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    William Ryder RPT
    Arcata CA
    (707) 822-3319
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  • 2.  RE: Bending let off dowel screws

    Registered Piano Technician
    Posted 03-17-2023 14:55
    William

    When you looked at the let off buttons did you see that the jack toes were hitting in the middle of the button, or the back edge?  If, after you replaced the parts, the jacks were now touching the buttons towards the back of the button, it indicates that the wippen rail slipped back just a few millimeters.  Instead of bending each button, move the wippen rail forward a millimeter. When you do this, you will also need to reposition the jacks under the knuckles. 





  • 3.  RE: Bending let off dowel screws

    Registered Piano Technician
    Posted 03-17-2023 17:17
    Greetings Bill,

    This sure sounds like growing action brackets to me. Have you ruled that out? Supply88.com sells replacement brackets.

    Cheers! 

    Ted Kidwell, RPT, CTE
    Kidwell Piano Works
    916 200 8747





  • 4.  RE: Bending let off dowel screws

    Registered Piano Technician
    Posted 03-17-2023 17:59
    Ted

    If this piano was indeed made in the 1980'2, Young Chang action brackets didn't become a problem until 1990. 





  • 5.  RE: Bending let off dowel screws

    Registered Piano Technician
    Posted 03-17-2023 18:02
    You're sure right about that, Wim. Bill didn't seem exactly sure on the date of manufacture. This problem sure smells like action brackets to me.

    Ted Kidwell, RPT, CTE
    Kidwell Piano Works
    916 200 8747





  • 6.  RE: Bending let off dowel screws

    Registered Piano Technician
    Posted 03-17-2023 18:54
    He said the action regulated well. The only problem was the let off buttons. 





  • 7.  RE: Bending let off dowel screws

    Registered Piano Technician
    Posted 03-18-2023 14:20

    I don't remember precisely, having worked for both YC and Samick, but I believe that YC did make some Cline brand pianos.  If so, and it was made in the 1980's, it would be a basic copy of the like model Yamaha of that era.  I'm pretty sure the spread should be 112.5 mm. Get that right before you try anything else.  Also, the YC action bracket issues didn't start until early 1990’s serial number range 50,000 when they switched from the gold brackets to the grey aluminum.  It was finally corrected in the early 2000’s around serial numbers in the low 100’s  maybe 112000



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    Philip Glenn RPT
    Mililani HI
    (808) 349-2943
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  • 8.  RE: Bending let off dowel screws

    Registered Piano Technician
    Posted 03-18-2023 17:19
    Hi Wim, Ted and Phillip,

    Thanks so much for your responses to my email.  I've serviced this Cline CG-510 since 2010 but I don't have the serial number written down.  I'll be going back soon to do some more work on it and I'll get the number.  I have a feeling that it may have been made in 95 or later, so I think you may be right about the expanding action brackets.  I'm not sure how to measure the spread, Phillip. Could you please let me know how to do that?
    Thanks again!
    Bill





  • 9.  RE: Bending let off dowel screws

    Registered Piano Technician
    Posted 03-18-2023 17:50

    You're welcome Bill

    The spread is the distance from the whippen flange center pin to the hammer flange center pin most YC grands were 112.5.    Blocking hammers is almost always the first symptom of "bracketitus". So if you've found yourself having to readjust letoff on an annual basis with that piano, and the brackets are grey in color, then I'd say you've got the problem.

    Contact Vincent Choi at (657) 233-1888 vincentchoi@pal-sound.com   He has new brackets from YC  

    I'd really hate to see you bend let off screws. I can't image the difficulty it would create in trying to regulate as they twisted around 

    good luck 

    phil 



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    Philip Glenn RPT
    Mililani HI
    (808) 349-2943
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  • 10.  RE: Bending let off dowel screws

    Member
    Posted 03-18-2023 19:29

    The Cline is on my list of pianos with possible defective action brackets along with Weber, Young Chang, Wurlitzer, Knabe and Piano-Disc pianos built by YC for piano disc. The serial number range is not absolute but it does narrow things down. I recently had a Piano Disc grand I had to replace the brackets on- they where so swollen in the frame I could not get the top stack off. That plus the fact it would not regulate. Brackets from YC/PAL are now $150 . I purchased brackets from Supply 88 for $100 but the customer cancelled the job stating I was ripping him off. The piano was a Joseph Pramberger Signature Grand that also had brackets stuck on the frame and would not regulate. I was selling the brackets at cost but 3-4 hours of labor to replace and regulate he expected me to negotiate   As for bending let off screws fuhgetabout it. If any break in the rail you will rue the day. There is something in the spread that is off or the dowels have been turned on the screws.



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    James Kelly
    Owner- Fur Elise Piano Service
    Pawleys Island SC
    (843) 325-4357
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  • 11.  RE: Bending let off dowel screws

    Posted 03-23-2023 06:15

    I "married" one of these actions last year when I replaced the brackets on a mid 90s YC.  When I first addressed the piano, I could not remove the action and told the customer to take it to the dump, but he was persistent and got the action out himself and then he begged me to replace the brackets.  I reluctantly agreed and  I got most of the action corrected, but there are 6 notes in the bass that are problematic.  They will play, but are sluggish in repeating.  I tried CLP on the center pins, then I tried strengthening the return springs, then I thought it was the knuckles and I replaced those but that has not helped, so in desperation, I ordered 6 brand new wippen assemblies.  I am going next week to replace them and hope that this helps those bass notes to play more consistently.



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    Patrick Greene
    OWNER
    Knoxville TN
    (865) 384-6582
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  • 12.  RE: Bending let off dowel screws

    Registered Piano Technician
    Posted 03-23-2023 06:45
    Patrick

    Before replacing the wippens, replace the centerpins on the flanges and the jack. But before your put in a new center pin, also burnish or ream out the bushing. On a lot of those vintage pianos, the bushing cloth is contaminated with some sort of chemical that causes a reaction with the nickel of the center pin. When you remove the pins, you will probably see that the ends are discolored. 

    The problem is, while this will most likely solve the problem of those 6 bass end reps, sooner or later the rest of the center pins will need to be replaced, too. 

    Wim





  • 13.  RE: Bending let off dowel screws

    Posted 03-23-2023 19:42

    Thanks Wim.  I will do that first.  



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    Patrick Greene
    OWNER
    Knoxville TN
    (865) 384-6582
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  • 14.  RE: Bending let off dowel screws

    Registered Piano Technician
    Posted 03-23-2023 06:48

    Check the spread of the hammer rail and wippen rail.  There are two different spread numbers depending upon what year the piano was manufactured.  If the spread is off, you'll get the problem you describe.  I don't have the specifics, but there's a sheet that should have been supplied along with the brackets that will identify which serial numbers and dates are for which spread dimensions.  I have this sheet, but not with me at the moment.  Maybe someone has that information on hand.



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    Paul McCloud, RPT
    Accutone Piano Service
    www.AccutonePianoService.com
    pavadasa@gmail.com
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