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Front Bushings Get Tighter

  • 1.  Front Bushings Get Tighter

    Posted 11 days ago
    I used a KBI, .010" larger than the pin. Initially they were fine. Within 30 minutes, they're tight. "Sup wit dat?

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    Regards,

    Jon Page
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  • 2.  RE: Front Bushings Get Tighter

    Posted 11 days ago
    Rebushed...or original?

    Pwg

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    Peter Grey
    Stratham NH
    603-686-2395
    pianodoctor57@gmail.com
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  • 3.  RE: Front Bushings Get Tighter

    Posted 11 days ago
    OEM, 1982, Stegler by Samick. Someone put graphite on all key bushings as well. The Balance rail seems to be doing fine.

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    Regards,

    Jon Page
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  • 4.  RE: Front Bushings Get Tighter

    Posted 10 days ago
    Maybe I should know Jon, but what is a KBI?

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    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
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  • 5.  RE: Front Bushings Get Tighter

    Posted 10 days ago
    KBI = Key Bushing Iron

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    Regards,

    Jon Page
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  • 6.  RE: Front Bushings Get Tighter

    Posted 10 days ago
    So, what's up with a 1982 piano with original bushings being this tight?  That's a different question.

    For yours, my guess, based upon recent experience rebushing a much newer Eisenberg upright, would be that the busing cloth used is very thin, and that there's little that can actually be sized.  The upright I did had key pins (at both rails) measuring around .125"-.130".  Yes, there did seem to be some variation.  The existing mortises (which I did not alter) allowed only the thinner sized cloth, in the .030" range.  I tend to prefer using KB cauls that are not oversized (ordered custom) when installing so that I can treat any that come out somewhat tight with KBI.  In this case, there was not enough resilient cloth remaining to respond to the compressive heat.  An additional problem presented, since, due to the minimal cloth thickness (and my unwariness), there was some occasional trace glue protruding from below the bushing which easily transfered to the iron.  No fun.  And no result.  I had to end up using ye old pliers on what felt like hardwood keys.  Fortunately, there weren't too many needing easing then, but I'm back to piano this week and will see what summer humidity has done.
    I've never used leather, but I suspect that KBI is not a sizing option with these.

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    David Skolnik [RPT]
    Hastings-on-Hudson NY
    914-231-7565
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  • 7.  RE: Front Bushings Get Tighter

    Posted 10 days ago
    Edited by Jim Ialeggio 10 days ago
    We had this on a new German keyboard recently...not posting the name, but to be clear this was not a Kluge keyboard...it was a different German company. This was unacceptable new work,and the kind of unbelievably wasted extra work that would keep me from ever ordering a new keyboard. Seized bushings, especially balance rail.  Sized the bushings with heated cauls and Profelt ...they regained the tightness (seized) over the weekend. Eased the holes a tad...regained tightness. Reduced the balance hole thickness...didn't work. Ironed them...regained the tightness. Eased them with a key easing tool...regained tightness. The felt used was simply too thick, for the given mortise/pin size. The entire keyset had to be rebushed with appropriate thickness cloth.


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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 8.  RE: Front Bushings Get Tighter

    Posted 10 days ago
    Back in 1988, when I began working at the store, we sold Samicks. My first job as apprentice was to remove each key and ease the bushings. Every single piano had sticking keys. I had to do both the bushings and the balance rail hole. I spent 8 hours a day taking keys out of the new pianos and easing keys. Later, we learned why this was happening. They factory was drying the wood too much in the kiln, and then immediately machining it. The wood would then swell up during transport. They changed the percentage of moisture content in the process, which cured the problem. I would suggest that this may be the problem, especially with a new keyboard.
    Paul McCloud
    San Diego



    Jim Ialeggio
    We had this on a new German keyboard recently...not posting the name, but to be clear this was not a Kluge keyboard...it was a different German company. This was unacceptable new work,and the kind of unbelievably wasted extra work that would keep me from ever ordering a new keyboard. Seized bushings, especially balance rail. Sized the bushings with heated cauls and Profelt ...they regained the tightness (seized) over the weekend. Eased the holes a tad...regained tightness. Reduced the balance hole thickness...didn't work. Ironed them...regained the tightness. Eased them with a key easing tool...regained tightness. The problem was there was simply too thick a felt was used, for the mortise size. The entire keyset had to be rebushed with appropriate thickness cloth.


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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026





  • 9.  RE: Front Bushings Get Tighter

    Posted 10 days ago
    MC% at fabrication was suggested to me when we were working on this.

    As a control, early on, we installed one set of properly sized bushings on one key. This key was stable throughout the entire month long easing mess. Assuming the mortise had reached its equilibrium dimension by this point, putting the appropriate felt thickness as per mortise/pin combo, was the ticket, and made sense...it worked.



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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 10.  RE: Front Bushings Get Tighter

    Posted 10 days ago
    Interesting but not completely clear.
    Paul's post is relevant to Jon's original in that they are discussing Samick's, and, in fact Jon's would appear to significantly pre-date n(1983) the correction Paul claims the factory made, subsequent to 1988. It certainly makes sense that an over-dried key would respond significantly to the Cape climate, but it's not clear how long the piano has resided there.  If, for a good portion of its life, one might expect that, had it been even moderately played, the wear on the bushings would have some effect, but this doesn't seem the case.

    Jim's experience is only relevant if Jon were to chose to rebush keys.  but in this case, I suspect the pliers are the most likely solution.

    Jim, I wonder if you could re-write your last description.  It's not as clear as it could be.  What MC%?  What exactly did you do differently?  What's your criteria for fit when mocking up?  How much play (if any) do you want in finished result? How much dimensional change would these mortises be expected to undergo, season to season?  Which is our 'more perfect' season?


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    David Skolnik [RPT]
    Hastings-on-Hudson NY
    914-231-7565
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  • 11.  RE: Front Bushings Get Tighter

    Posted 10 days ago
    David,

    I think these are all equivalent scenarios.  Here is the concept:

    In the case of a keyset of any provenance being machined at too low an MC, the relevant physical result will be that in very short order, after fabrication, the mortise will shrink. This shrinkage will be greatest in the initial return from hot box dried conditions to ambient conditions. This return to equilibrium will occur at a time pretty close to fabrication.  After the initial change from hot box to ambient conditions, in service, in normal service ambient conditions, the size of the mortise will be relatively stable. This relatively stable mortise dimension however, will be smaller than intended...permanently.

    In the case of ineffective, repetitive field easing, the extant problem is that there is now too much felt in a relatively stable but too small mortise.

    Now that the wood is at a reasonable ambient service MC, the extant problem is that the mortise is too small for the thickness of felt they installed at fabrication.  That is, the fabricators thought the mortise was going to be wider than turned out to be the case. Easing till the cow's come home will not correct the extant problem of too much felt in the mortise. Only removing felt will correct the problem. Depending on how much the original mortise shrank, relative to how thick a felt they used, the problematic bushings may only become apparent, in certain ambient conditions.

    In the original case Jon described, when easing was ineffective after a short wait period, having gone through this dance, I would encourage him to jump ship early and save some time. Given the evidence, the likelihood is low that the easing he tries will be reasonably permanent.  In our case it actually took a couple of weeks on the last try before the mortise seized again.  Why? there is simply too much felt in the mortise. Excessively crushing wood fibers to open up the mortise does not appear to produce a stable mortise dimension.

    As far as fabrication MC. It would make sense for a fabricator of a new set to be targeting a mid point in normal ambient service conditions. 8% would be my target...keeping in mind moisture meters have a +/- 2% error, triangulate this measurement somehow.  When I'm working on extant keys, I want them at ordinary expected service MC's. Its not a soundboard, so its not going anywhere near a hot box.

    When old keys come into the shop,  one can assume, unless there has been a flood, that they have equalized at ambient conditions long ago, and are safe to size mortises and select felt.  Confirm the mc with a meter and have at it.

    In all the scenarios where the keyset is too dry, chances are great that it is a new keyboard , and that is has been jammed and accelerated through the fabrication process to meet administrative production timelines.


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    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
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  • 12.  RE: Front Bushings Get Tighter

    Posted 7 days ago
    Edited by Jon Page 7 days ago
    The pins are .140". I first used a .147" caul and they returned to having no minimal side-play. I then used .150" and the same thing happened. Yesterday, I opted for .155" and they are still good today with minimal side-play.

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    Regards,

    Jon Page
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