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Bosendorfer leather key bushing friction

  • 1.  Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 08-24-2021 20:01
    Hello all, I'm working on a Bosendorfer Imperial Grand from 1963 that has excessive friction at the leather key bushing/key pin interface.  Is there a way to clean and soften the leather?  I'd appreciate any response.  Thanks.
    Bill Ryder


  • 2.  RE: Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 08-26-2021 12:12
    Hi William,
    I've been experimenting with leather key bushings and in my limited experience you just have to put up with more friction in leather keybushings. You just can't expect the same buttery feel you get with high quality, properly sized and lubricated felt.

    Roger Jolly was promoting leather on the balance rail and felt on the front rail as the best of both worlds, I have tried this a couple of times and it seems fantastic: The idea is that the increased support and longevity of the balance rail, will help slow down wear on the front rail.

    If you can't replace the front bushings with felt, I would try roughing up the leather with a small file and working teflon into the leather. I haven't had much luck with liquid lubricants on leather.

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    Ryan Sowers
    Olympia WA
    360-705-4160
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  • 3.  RE: Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 08-26-2021 15:41
    I have never used leather bushings, but many who have tell me they swear by Ballistol as a lubricant.

    Sent from my iPhone





  • 4.  RE: Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 08-26-2021 16:33
    Mr. Ryder, While I'm also a fan of Ballistol in your case I'd recommend lubricating the key pins with a dry film lubricant. I like McLube Sailkote or Mac 444(identical lubricant by same company with different solvent mix) applied with a small artist brush. That way you don't have to worry about the Ballistol reacting with any other lube that may have already been applied to the leather.

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    Karl Roeder
    Pompano Beach FL
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  • 5.  RE: Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 08-27-2021 10:41
    I have a client with an 1880's Blüthner who insisted on leather keybushings. He's also very sensitive to key friction so it's been an ongoing battle.

    When I first rebushed, I polished the pins with Flitz, and sprayed several coats of dry film Mclube on them. They felt great!

    But it didn't last, and next time I showed up for servicing it was very disappointing how much friction was in the keys.

    Then I switched to Balistol, and again, they felt great - for a little while. Since the key slip pops out so easily on this piano (it just slides downwards) it might work out well to give him some lubricant in a bottle with a little artist brush and he can brush a little bit on his pins as needed.

    One issue to keep in mind if you are thinking about rebushing with leather - the rough side goes against the pin. This seems counterintuitive and I opted for the smooth side in the case of this Blüthner. After going back and reading some of Roger Jolly's writing on this, he recommended the rough side against the pin, and working dry Teflon powder into leather. But, again, Roger's recommendation is leather on the balance rail only.

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    Ryan Sowers
    Olympia WA
    360-705-4160
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  • 6.  RE: Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 08-28-2021 06:01
    I would be concerned that the Balistol will eventually contaminate the key wood. I’ve never found a way to fix that if that happens.
    Bill




  • 7.  RE: Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 09-02-2021 17:04
    We were introduced to Ballistol (weapons oil) in Germany as an excellent cleaner and lubricant for metal parts, developed for use on guns. But we were cautioned NEVER to use it on cloth or leather in piano work. The oil will collect dust and dirt, cause gummy friction and then is impossible to clean out of those materials.
    When we worked with Kluge, Mr. Narath (from the founder's family and owner of the company at the time) told us that some piano builders and manufacturers specified the smooth side of the leather bushings toward the pin and others asked for the rough side. We always used the rough side toward the pins on both the front rail and the balance rail. That seemed to be the closest to using cloth and was able to be manipulated like cloth.  In our experience, leather lasts a really long time - like 100 years - with no adjustments necessary.  (No we are not that old, just have had experience with grands with leather bushings that have been in the keys for over 100 years).
    If there is too much friction we, like Ryan, make sure the pins are very clean and ensure that the front rail pins are not twisted in any way. The leather can be eased with the normal easing pliers especially if the rough side is toward the pins. If the leather gets hard and starts to make a noise, the leather can be needled or even roughed up with sandpaper then eased as necessary. The only "lubricant" recommended by our knowledgeable friends in Germany is very fine talcum powder dabbed or rubbed into the leather.
    A few of our supply houses have leather bushing strips in various sizes; check it out if you are thinking of rebushing a whole keyboard. There are tricks to installing leather bushings.  As an aside, we were working with Ryan some years ago to give a class specifically on leather bushings which would have included all of the points in this discussion when the Executive Committee at the time or some sub-group of them quite rudely dis-invited us from teaching.  Ancient history I guess.
    If this has been of some help to some people, I am glad.
    Joel

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    Joel Rappaport
    Rappaport's Piano Workshop
    Round Rock TX
    512-255-0440
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  • 8.  RE: Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 09-03-2021 08:18

    I've been using cut down Balistol  ( 50/50 with naphtha) for over 10 yrs. and have not experienced any collecting of gummy residue issues. That being said, I never use it straight out of the jug.  Always diluted 50/50 with Naphtha.   That has become my go-to for action centers and it does an excellent job. Cloth key bushings seem to work with this solution as well. And it does a remarkable job with buying time with all of those Verdi Gris action issues.

    I did have one horrible experience with a failure, as the Balistol/Naphtha collided when I experiment Titebond Molding glue on a key bushing job.  The bushings all fell out.

    Hot Hide glue and Balistol have shown no issues over the 10 yr. period with my installations.  Also as a note, Balistol claims is that it's also can be used an excellent leather conditioner.

    My 2 cents....

    Tom Servinsky 

    Registered Piano Technician

    Concert Artist Piano Technician

    Director/Conductor- Academy Orchestra

    Managing Conductor-Treasure Coast Youth Symphony

    Clarinetist-Atlantic Classical Orchestra

    tompiano@tomservinsky.com

    Website: tomservinsky.com

    772 221 1011 office

    772 260 7110 cell

     






  • 9.  RE: Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 09-03-2021 10:02
    Having now done two complete leather key bushings, there was definitely a learning curve to both the selection of the leather and its application.  We have two leather suppliers here in Eugene and I was able to select some excellent materials.  The thickness was the crucial and the samples I had exposed a distinct difference in "traction" between the smooth side and the suede side.  Perhaps this contributes to the choice at installation.  We chose the suede side for our Bluethner.

    I seem to remember a class that Sally Jamieson taught where the advice, in addition to the Teflon/talc, was to use a small brush to raise the nap of the leather.  The smooth side doesn't seem to have that.  The brush recommended was on similar to what we use to clean between the teeth.  They come in straight and tapered and actually work quite well.

    Also, it seems in most cases in the leather bushed keyboards of old that the key pins are not plated nor are they oval.  Both of these conditions would seem to add to the traction of the pin.  We did a good deal of polishing on the pin to get it as smooth as possible and used MAC 444 or similar to help the cause.  Three years later it is working as we set it up.

    While we did not get to a "modern" feel out of the keyboard, we did get to a point where the side friction component of the touch measurements started to make sense.  The keys are very, very quiet, supremely accurate for the side to side play and contribute to the piano's historic nature.

    Let's see would I do it again?  Sure!!!  But…….plan and budget for the extra time to accomplish.
    Mike Reiter, RPT
    Chair, CAUT Committee
    Piano Technician, University of Oregon

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    Michael Reiter
    Eugene OR
    541-515-6499
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  • 10.  RE: Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 09-03-2021 13:05
    Tom S does rightly observe that "Also as a note, Balistol claims is that it's also can be used an excellent leather conditioner." However, if you look further at the Ballistol site in English:
    https://ballistol.com/uses/leather-care/
    It mentions and pictures various leather articles:  shoes, gloves, even your boots, holster and saddle! You will see that all of these items show the smooth surface of leather and Ballistol is very good for that.  However, notice that it does caution as follows:
    "However, being an oil after all, BALLISTOL SHOULD NOT BE USED ON SUEDE FOR OBVIOUS REASONS."  Assuming that the rough side of the leather bushing is toward the keyboard pins as we use it, I think that would qualify as "suede."  Use on that surface is not recommended by the manufacturer of Ballistol.
    But hey!  If it works for you either straight or in solution, more power to you!  Let's check back in 100 years and see how it's going.  :-)
    Joel

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    Joel Rappaport
    Rappaport's Piano Workshop
    Round Rock TX
    512-255-0440
    ------------------------------



  • 11.  RE: Bosendorfer leather key bushing friction

    Registered Piano Technician
    Posted 09-04-2021 05:03

    Well....let's put a check mark down for 10yrs ( and counting) with no issues using Balistol in the cut-down method with naphtha 50/50

     

    Tom Servinsky 

    Registered Piano Technician

    Concert Artist Piano Technician

    Director/Conductor- Academy Orchestra

    Managing Conductor-Treasure Coast Youth Symphony

    Clarinetist-Atlantic Classical Orchestra

    tompiano@tomservinsky.com

    Website: tomservinsky.com

    772 221 1011 office

    772 260 7110 cell