[CAUT] center pinning changes/ long pin method

[Fred Sturm]

Hi Jim,
	Can you describe the long pin method? We discussed something along  
those lines on this list a while back, but I never got all the  
details. I understand one is using pins long enough to go through  
several flanges, but I'm not clear how exactly one proceeds. Does the  
whole length of the long pin get pushed through the bird's eye of  
each flange? That seems awfully cumbersome and potentially a bit  
destructive.
	Joe Goss has long burnishers - very long as in a meter or so - for  
all American sizes of pins, and those can be used as you describe for  
pulling through the bushing. I must say I am a bit skeptical about  
the idea that it makes much difference doing the pulling in one  
direction, but maybe you're right.
	 In burnishing center felt, it seems to me that the burnisher is  
going to be pressing against the felt hard enough that fibers  
wouldn't be able to move around, at least significantly. At this  
point in my own work I mostly do a rapid back and forth action, fast  
enough and enough of them to create a good bit of heat. (You can get  
heat pulling the burnisher through all the way rapidly, but  I think  
I get more heat faster by doing back and forth, as the metal of the  
burnisher heats up). That seems to set the felt quite nicely. And it  
seems to be possible to move up a half size to a full size just using  
burnishing action without removing any felt, just the ironing action.  
I haven't been doing it this way long enough to have a good sense for  
longevity and whatnot, but it seems to be good so far. Certainly  
makes sense, as long as the felt in the bushings doesn't swell later,  
maybe due to humidity rise, and make the centers sluggish, and I  
haven't found that in university pianos, which get quite a bit of  
use. Of course I am dealing with my own humidity environment, which  
is typically 10% to 60% range.
Regards,
Fred Sturm
University of New Mexico
fssturm at unm.edu



On Sep 10, 2007, at 12:48 PM, Jim Busby wrote:

> Hi Ted,
>
> Just some feedback on the "long pinning method" you mention below
> (Thanks Jurgen!). I have been doing this for quite a while now and it
> seems to have much more longevity and be more stable than other  
> methods.
> I think it is because the long pin pulls one direction through the
> center, thus "combing" the fibers in one direction and packing them in
> tight. When I use other back and forth burnishing techniques and  
> "shake
> down" the parts the grams may go from say 5 to 4 or 3 until they  
> become
> immovable. With the long pinning method there is no "shaking down"
> necessary or possible. Either way is good and can be done to  
> perfection,
> but this "European way" is becoming my preferred method because of  
> this
> instant and permanent stability and better longevity. Better Longevity
> means that I repin about every 3-4 years instead of every 2-3  
> years. It
> may be even better than that because I'm at about 4 years since I
> started using the method and some are still good!
>
> Regards,
> Jim Busby BYU

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