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"Dry" flange bushings

  • 1.  "Dry" flange bushings

    Posted 02-22-2018 12:06
    Hello all,

    I have a client with a 1989 Ibach grand that has had persistent tight jack flange bushings. After the second time of repinning the problem jack and lubricating the rest with CLP, the client has decided to go ahead and have me repin all of the jack flanges. It seems like the flanges that are getting the most use are the ones that have been flaring up. I have checked for centre pin plating problems as well as centre pins loose in the birds-eye, but both have checked out OK.

    Now that the action is in my shop, it seems like most of the jack flanges are OK, but many of the wippen flanges are very tight. When I am repinning, however, the feel of the pins in the bushings is odd. The bushings seem "dry". It seems like there is a lot of friction between the pin and the bushings, even when the bushing is reamed/burnished to a good size. There is also often a lot of static vs dynamic friction once the parts are pinned together again. I am guessing that this has to do with the original cloth being low-quality, perhaps with all of the lanolin stripped out. I am not in the habit of lubricating bushings when I am repinning, but I have heard of others doing that. Is this the kind of scenario that would call for that treatment? Anything else I am missing? I am a little concerned that using my standard protocol might leave the bushings susceptible to side-to-side play with continued use down the road.

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    Peter Stevenson RPT
    P.S. Piano Service
    Prince George BC
    250-562-5358
    ps@pspianos.com
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  • 2.  RE: "Dry" flange bushings

    Posted 02-22-2018 15:05
    That piano will have a Renner action, so the chances of encountering low quality bushing cloth is probably quite slim.  Renner has applied graphite to busing cloth at least during some recent eras - that could be a source of a problem.

    I always have some CLP handy when re-bushing sets of centers.  It can't hurt to have a bit of lubricant in there, especially if the center pins are doing what you say.  Also, check the center pins you are inserting to make sure they are nicely polished.

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    Jurgen Goering
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  • 3.  RE: "Dry" flange bushings

    Posted 02-22-2018 15:57
    I dip the Maninno Brunisher into powdered Teflon and apply it to each side before burnishing. It works the Teflon into the felt.

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    Regards,

    Jon Page
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  • 4.  RE: "Dry" flange bushings

    Posted 02-22-2018 16:40
    This seems to be a Daewoo Ibach. I know that Daewoo didn't buy out the company until 1991, but the serial number matches up to a 1989 Sojin. In any case, I don't think that it has a Renner action. I will experiment with CLP and teflon. When you apply the CLP when you are repinning, at what point do you apply it? I don't want to get a "false reading" by thinking that the centre is free and then having it seize up in the customer's home.

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    Peter Stevenson RPT
    P.S. Piano Service
    Prince George BC
    250-562-5358
    ps@pspianos.com
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  • 5.  RE: "Dry" flange bushings

    Posted 02-22-2018 17:51
    You may want to at least REBUSH and REPIN a few of them because you may ultimately have to that especially if the bushing cloth has had some graphite or other material added or the cloth was poor quality. It sounds like the Young Chang seizing center pin scenario. Also consider getting your center pins from WN&G

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    James Kelly
    Pawleys Island SC
    843-325-4357
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  • 6.  RE: "Dry" flange bushings

    Posted 02-22-2018 22:47
    That it's Daewoo makes more sense.   I haven't had this problem with Renner actions, but it's quite common with Young-Changs and some other Korean makes.  The popular explanation for this problem seems to be poor plating on the center pins.   I don't buy this for two reasons:  I haven't observed this to be the case when examining the center pins & I'm not convinced the center pins are even plated to begin with.   A more likely explanation is that whatever glue they used to secure the flange bushing cloth has wicked through the poor quality cloth.  Who knows what kind of adhesive they used? They're so many to choose from nowadays.   But it's the adhesive that's grabbing at the pin.

    I say grabbing, which is subtly different than just being tight in the cloth.  You can ream them out to a proper size to fit the pin and when you test it for feel they still seem to "grab" at the pin.  I rub a little oil from my forehead on the new pin before inserting it.   Then it feels good.  I'd have little more faith in CLP if they were a little more straight forward about what's in it.  When I was a kid "space-age" sounded really cool.  Now SpaceX is just another aerospace company down the street, and the term has lost some cachet.

    If I'm in the field and there are just a few tight centers, repinning is expedient,  but If I'm right about the the cause, then it makes more sense to get at the root of the problem by rebushing the action centers.  Which is more work of course but not that much more--after all the work you've already invested by bringing in the action into the shop and taking the parts off and putting them back on and all that entails.  But you will be sure it won't come back to haunt you.  A characterstic of this problem is that centers which have been trouble free for years can suddenly seize up on you.  You can squirt Protek on everything, but you know how people's minds work: once you've repinned a few, you own all the faults.

    I like Renner flange bushing cloth.  I haven't found anything better and there's no reason not to use the best since the real expense here is all in the labor.

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    Cecil Snyder
    Torrance CA
    310-542-7108
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  • 7.  RE: "Dry" flange bushings

    Posted 02-22-2018 23:12
    Edited by Chris Chernobieff 02-22-2018 23:14
    What about the Birdseye in the fork? If that's tight that could cause hard to find friction.
    -chris
    #caveman