CAUT

  • 1.  Parts replacement Drop Cushions & Knuckles

    Posted 20 days ago

    Hi Gang:

    As I get up to speed in the university setting, and more familiar with S&S (I'm a Yamaha/Bösi man) I'm getting crazy loud clicks from knuckles and drop screw cushions, but not on the same pianos. 

    The hammers and whippens on these pianos look fine, though most of the hammers need some reshaping. 

    I'm  trying to do an on the fly cost benefit analysis. For $200 in parts and a day's labor I suppose replacing a knuckle seems to make sense. But outside of the occasional knuckle replacement over the years, I have never replaced  a complete set.

    I did pull one of the weapons and replace the drop screw cushion with new buckskin and what a surprise… It's now silent. A set of weapons is closer to $1500'ish I believe off the top of my head. 

    For those of you who have done both approaches or considered both approaches which way do you generally go? The action on one  Steinway D from 1927 has a new'ish action and key buttons and loud drop cushions. 


    Another  is a 1960's era D also with a new'ish action but I'd swear someone dipped the knuckles in CA glue they're so hard. 

    Edit: drop screw buckskin is super easy to replace. Makes me look like a wizard. 

    Thanks in advance,



    ------------------------------
    Vincent Chambers

    Apollo Piano | Stanford
    San Francisco, Chico CA
    (530) 924-4469 Mobile; 732-642-1100
    ------------------------------



  • 2.  RE: Parts replacement Drop Cushions & Knuckles

    Registered Piano Technician
    Posted 20 days ago

    I have replaced sets of knuckles, but I have not had occasion to replace drop cushions.  I think the answer is to follow the results of your diagnosis.  Where replacing the drop cushions eliminates the problem, don't worry about the knuckles, unless it is clear that replacing them would further improve the action.  If your knuckles on the other piano are are rock hard, replace them, and deal with drop cushions only if a clear reason presents itself for doing so.



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    Floyd Gadd RPT
    Regina SK
    (306) 502-9103
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  • 3.  RE: Parts replacement Drop Cushions & Knuckles

    Registered Piano Technician
    Posted 20 days ago
    Before replacing knuckles, brush them with a suede brush, and if necessary, yarn them.  Use the brush also on the drop screw leather. 





  • 4.  RE: Parts replacement Drop Cushions & Knuckles

    Posted 20 days ago

    Hi Wim!!! Good tip. But these seem like someone doused them with thin CA glue for some reason. Or something else happened. 

    they are like rocks. Weird stuff. 



    ------------------------------
    Vincent Chambers

    Apollo Piano | Stanford
    San Francisco, Chico CA
    (530) 924-4469 Mobile; 732-642-1100
    ------------------------------



  • 5.  RE: Parts replacement Drop Cushions & Knuckles

    Registered Piano Technician
    Posted 20 days ago
    I have done a whole set of knuckles.  It's really not bad, and makes a LOT of sense if the hammers are still in good shape.  You could probably even repin the hammer flanges while you're at it (if they're old they're probably too loose), and still come out ahead.  The actual work of removing and gluing in the new knuckles doesn't take but a couple hours max -- most of the "fun" is in reregulating.

    Crescent GG010 "Heavy Duty End Nipper" pliers are great for extracting the old knuckles (this is what the supply houses sell as "knuckle extracting pliers".  Use your judgment as to whether the original glue joint needs some help from a razor blade to come apart without damaging the shank.  A lot of times it'll pop them right out safely.  Stick the new ones in with hot hide or fish glue.

    I used the replacement knuckles sold by Abel, and they're are really nice and consistent.  But I would check out the new silicone core ones from WNG now -- they weren't available at the time.

    Replacing drop screw cushions isn't bad either.  Ecsaine seems like as good of a material as any.





  • 6.  RE: Parts replacement Drop Cushions & Knuckles

    Posted 20 days ago

    Great tips! Haven't tried the WNG knuckles, so that might be an option. 



    ------------------------------
    Vincent Chambers

    Apollo Piano | Stanford
    San Francisco, Chico CA
    (530) 924-4469 Mobile; 732-642-1100
    ------------------------------



  • 7.  RE: Parts replacement Drop Cushions & Knuckles

    Registered Piano Technician
    Posted 20 days ago
    Knuckles go pretty smoothly as long as you confirm ahead of time that the geometry is precisely the same (thickness of the cores and diameter). Pull off a knuckle and see that a new one will fit the slot tightly. A little loose can be OK, but then you should put all the shanks in a clamp, evenly aligned, so when you install the new knuckles to can be sure they are all perfectly aligned - use a straightedge.

    Another option for hard knuckles is to insert a wire (perhaps a Mannino broach) between leather and core, and run it around between the core and leather, which will exercise the leather. It might be enough to reduce noise, together with a good brushing and/or possibly sanding to remove a hard surface glaze..

    Drop leather replacement is best done removing all the wippens and setting up an assembly line process. Depending on the glue, it might make sense to soak off, or alternately to chisel off (rep lever in a vise, sharp chisel). Replacement material needs to be carefully chosen for thickness that matches precisely, or you will be doing a lot of drop screw turning. Also take care that the new material doesn't extend beyond the end of the lever, or it will rub on the hammer rail. 

    It's a good idea to look at each instrument with an eye to the long term. What do you see doing to it in the next five to ten years? And that needs to be balanced against money and time. If you have a big parts budget and not much time, parts replacement is favored. If the opposite, reconditioning is favored. 

    And if, as is commonly the case, both time and money are scarce, you just do the best you can :-)

    Regards,
    Fred Sturm
    fssturm@comcast
    "The cure for boredom is curiosity, and there is no cure for curiosity." Dorothy Parker






  • 8.  RE: Parts replacement Drop Cushions & Knuckles

    Registered Piano Technician
    Posted 19 days ago
    I recently replaced knuckles on a Feurich grand; about 40 years back, on the same piano, I put in Renner knuckles, and before the recent replacement these were the hardest I'd ever encountered.  Really noisy.  This time around, I used WNG parts; they make two types, one for wood shanks and the other, presumably, for their own shanks.  Of course I used the ones intended for wood shanks.  The cores were plastic of some kind, and too thick for the slots, but I found I could compress them with parallel pliers easily.  Another thing to watch out for in the job is making sure that the knuckle core is seated all the way in the slot, and on both sides.
    The trouble with the core material being too thick may not be an issue with Steinway parts, the shanks on the Feurich dated from about 1900, and were of the Renner type.
    Ken

    Historicalkeyboards.as.cornell.edu





  • 9.  RE: Parts replacement Drop Cushions & Knuckles

    Posted 17 days ago
    Not only are these knuckles hard, they are far from being seated. 
    Vintage S&S D w/ rebuilt action very hard knuckles not seated properly


    ------------------------------
    Vincent Chambers

    Apollo Piano | Stanford
    San Francisco, Chico CA
    (530) 924-4469 Mobile; 732-642-1100
    ------------------------------



  • 10.  RE: Parts replacement Drop Cushions & Knuckles

    Registered Piano Technician
    Posted 17 days ago
    Definitely would improve with a knuckle replacement job :-)  Possibly that's a source of the noise as well.
    Regards,
    Youtube Spotify Deezer Apple Amazon
    www.artoftuning.com
    http://fredsturm.net
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda