Flange Repinning (was: Mystery Residue)

[Jon Page]

Rob,
My c/p nippers from Pacific Piano Supply make a nice clean cut.

I just performed this expreiment:
Nipped a center pin and examined it under a loop.
I observed a slight peaning-over of the pin where the jaws first cut
into the pin with no peaning at the ends of the final shear point.

I then flied the end and observed a swage of metal pushed off the
side of the pin.

I concluded that filing the pin would cause the end of the pin to tear
at the bushing cloth more than the slightly peaned edge of a cut pin.
The filing actually left the pin ragged on the end. I don't recommend this.
Finished c/p's would be the only way to have a clean edge on both ends.

Examining the cut pin reinforces my theory to push the pin from the
uncut side while removing so as not to enlarge the birdseye further
with the peaned edge.

But my thought on filing was not on the pin but on the wood surfaces to
burnish for the purpose of reducing drag/friction.

The repinning went superbly. Was that residue a sizing for the felt?
The last mid 80's vintage S&S had spongy bushings, these were perfect.
If it were some type of lube/sizing, I would not hesitate to use it in the
repinning process if it produces results as it did here (if it did). I
hesitate
to attribute the freeness of the pinning without wobble on the burnishing
of the surfaces while removing the residue.

I'll test the theory on the next set:  burnish a few, just repin a few others;
evaluate difference.

Back to work,

Jon Page
Harwich Port, Cape Cod, Mass. (jpage@capecod.net)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

At 06:16 AM 12/11/98 -0500, you wrote:
>Jon,
>I've found that filing the end of the center pin definitely reduces drag -
>for how long I can't say,  but filing heats the pin and gives more swings.
>
>Rob Stuart-Vail
>-----Original Message-----
>From: Jon Page <jpage@capecod.net>
>To: pianotech@ptg.org <pianotech@ptg.org>
>Date: Thursday, December 10, 1998 9:36 PM
>Subject: Flange Repinning (was: Mystery Residue)
>
>
>>List,
>>It seems the material was applied to the flanges since the residue was on
>>the outsides of some of the bushings as well as the outside areas of the
>>birdseyes. Filing with a fine file removed the crusty residue and also
>>burnished the surfaces. Which got me to thinking, hmm; I wonder if
>>filing/burnishing all shank yokes and flanges prior to repinning would help
>>to reduce drag on these surfaces. Not so much as to remove material but
>>just to burnish.
>>
>>Some flanges insert tightly and this must certainly add to friction. Over
>>time, the grain raises or the surface becomes rough, so by
>>filing/burnishing these surfaces wouldn't this be a good procedure to
>>include in the repinning operation?
>>
>>I don't know what the residue was, oat meal bath? I didn't taste it. It
>>left traces on the tops of the yokes, with some on the outsides of some
>>bushings and concentrated around the outside of the birdseye/yoke.
>>
>>So it was something in suspension which hydrodynamically adhered around the
>>birdseye and subsequently dried which resulted in an abrasive drag to the
>>rotation.
>>
>>Having gotten this far, I'll repin in the morning.
>>
>>Jon Page
>>Harwich Port, Cape Cod, Mass. (jpage@capecod.net)
>>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>
>>At 08:21 AM 12/9/98 -0500, you wrote:
>>>S&S  S    c. 1985
>>>grinding sensation in hammer swing test. beige residue on birdseye and
>>shank yoke.
>>>It is on the outsides of some of the bushings also. Is this a
>>>PVA glue which has leached out and dried to form this crust?
>>>The pinning is not tight but there is drag caused by this residue so I
>>>will repin and file the surfaces clean.
>>
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