Rebushing centers/mystery center pinning

[Robin Hufford]

Hello Richard,
    I am unawares of the "new" bushing and can't speak to their 
characteristics as delivered from the factory, as you say.    I made 
these observations  based upon Barbara's description of the results of 
repining.  This sounds like an overly soft bushing as I said.  I have no 
direct knowledge of any new bushing material from Steinway as I seldom 
use these kinds of parts from them anymore.  Obviously, if they are not 
too soft then there would be no need to harden them but their behavior 
seems to indicate they need such treatment, or at least this particular 
set does.   However, simply because the claim is made that the bushing 
is hard doesn't mean, in my experience, they will be, perhaps yes, 
perhaps no, perhaps sometimes and one probably will not know when until 
perplexing difficulties arise. 
     One can  take the hammershank and flange in hand and hold the 
flange tightly while trying to wiggle the shank in a way so that the pin 
can be made to move back and forth in the bushing and watch this 
motion.     A soft bushing will show  more motion of the pin in the 
bushing  and that is a serious problem as it has a really detrimental 
effect on the sound.   I don't know exactly how much motion looks to be 
too  much myself except that if I can burnish and repin, or use a 
treatment and hear an improvement in the  sound then the amount of 
motion of that particular pin was too much:  this suggests the rest are 
likely to be similarly problematic  and the set needs to be either 
repinned,  shrunk  and repinned , rebushed, or densified perhaps as I 
describe. 
       Sometimes, as I Barbara and I both have experienced, repining is 
only a temporary improvement; in the face of such a frustrating 
experience I tried the method I described.   It appears, as I said, at 
least for the moment to have both worked at the time of use in 
stabilizing the friction and wobble and led to no discernible subsequent 
pining problem.   But, again, its purpose was to deal with an overly 
soft bushing.  If I were Barbara in this situation I would find two or 
three really weak sounding notes from the middle and low treble and 
change nothing else but the density of their bushings with the mixture, 
or take the time to use water with alcohol, and judge from the results.  
I think is absurd even to have to do this lesser task by necessity but 
even more so  when  it is necessary to take the time to rebush  parts 
for which one has already paid good money to have acceptable bushings 
come along with the rest of the order.   I'll have to climb down off my 
soapbox here before I get myself really worked up!
Regards, Robin Hufford 
Richard Brekne wrote:

> Hi Robin,
>
> Nice and informative posting. However I am a bit perplexed here. The 
> bushings in question are of the new Steinway type as I understand it. 
> And it has been stated that these employ a very dense bushing felt 
> with some kind of teflon impregnation.  If that is so, then it 
> shouldnt be necessarry to take steps aimed at dealing with too soft a 
> bushing felt... yes ?
>
> Are you under the impression that these new Steinway bushings employ 
> inadequately densified bushings as delivered from the factory ?
>
> Cheers
> RicB
>
>
> Robin Hufford wrote:
>
>>      They are very unlikely to stay there long at all.  Again, the 
>> problem that I see, judging from your description is likely  do to an 
>> overly soft  bushing cloth have been used.  They may well, actually, 
>> have been sized at the factory but this effort has not densified the 
>> bushing sufficiently, which was probably too soft to begin with.  The 
>> use of  water again, may render them acceptable,  although I doubt 
>> this will occur.
>>        In my opinion, it is necessary to do something due to the 
>> overly soft cloth, which is similar to what one does when rebushing 
>> keys, that is, through a similar process to the glue-sizing done 
>> when  replacing key bushings which  allows the glue in that case to 
>> wick into the felt and size them to a certain dimension.  While we 
>> are not actually trying to size the bushing, I think to a certain 
>> dimension, we are trying to increase its functionaly density which 
>> impregnating the felt matrix with a very thin deposit of plastic 
>> does, I believe. 
>
>
>
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