[CAUT] center pinning changes/ long pin method

[Jim Busby]

Fred,

 

Ask Jurgen to describe it because I do it differently than him. I DON'T pull it through the birdseye like Jurgen does. I tried it and it works, but I'm afraid of the long term effect on the wood. Jurgen uses the long pin as the actual pin, cut off to remain there. I don't do that either, but use it only as a burnisher.

 

Here's how I've been doing it;

 

The burnisher I use is 2 feet long with a ground tapered/smoothed point on one end for insertion and about 1 ½ inches in is a mild reamer (roll between two files, but not too rough). I push/pull the entire length through the bushings until I can "feel" it has the right friction. (Test w/gauge) This takes 2 or three tries to get used to. Sometimes I'll pull it through one time, sometimes it takes two or three to get the right friction. When you get this feel down you can go quickly (as fast as you can pull it through)

 

As I stated before, the beauty of this method seems to be that whatever friction you get is final. No "shaking down" needed or possible. My observations are that other methods seem to relax or loosen a gram or so, but not with this method.  

 

I guess you could say I used a modified Mannino/Jurgen method. The important thing seems to be that the felt is "combed" one direction. I don't know whether this is bogus or not, but hope our student "scientists" can get an electron microscope pics of both kinds of bushings after each procedure. Seems to work for me!

 

Jim Busby 

 

________________________________

From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Fred Sturm
Sent: Tuesday, September 11, 2007 10:31 AM
To: College and University Technicians
Subject: Re: [CAUT] center pinning changes/ long pin method

 

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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