[pianotech] First Pinblock

[Dale Erwin]

Ron-you wrote--
People have for years been trying to tell me that tuning pins move back against the plate holes because the block rotates, ignoring the wide 
contact surface between block and plate that would prevent that.
Ron N


On epoxy bedding pinblocks in general, I consider it necessary. Looking at old pinblock takeouts,
 I often see a millimeter of crush along the  plate flange-  
Ron N


 I would think that a mm of pinblock crush crush would account for the block moving forward enough under 40 K lbs
of string pressure to cause pins leaning against the plate holes that we often see in aged pinblocks,...
 Especially in the bass where string tension is highest and plate holes often mysteriously the smallest.
 Dale




Dale Erwin R.P.T.
Erwin's Piano Restoration Inc.
 Mason & Hamlin/Steinway/U.S. pianos
www.Erwinspiano.com
Phone: 209-577-8397

 
  





-----Original Message-----
From: Ron Nossaman <rnossaman at cox.net>
To: pianotech <pianotech at ptg.org>
Sent: Mon, Feb 4, 2013 6:09 am
Subject: Re: [pianotech] First Pinblock



My first and continuing thought on the upright pinblock replacement, is 
how much of the other $20K+ of needed work is getting done with the 
pinblock replacement?

On epoxy bedding pinblocks in general, I consider it necessary. Looking 
at old pinblock takeouts, I often see a millimeter of crush along the 
plate flange. Soaking that flange fit in epoxy on installation will 
reinforce that wood that is in immediate contact with the plate flange, 
and both reinforce and fill the minute gaps where it isn't. So instead 
of areas of high pressure contact next to areas of low pressure or no 
contact, the contact across the entire flange is uniform and as low 
pressure on average as possible, backed up by a thin layer of 
compression resistant epoxy impregnated pinblock material. The resulting 
crush resistance, I think, is where the improved stability comes from.

For what it's worth, I only apply the epoxy as the plate goes in for the 
last time. I never saw the point in epoxy fitting the block to the 
flange, then taking it apart again. It does occur to me that for those 
who top fit blocks, that might make an easy separate step.

Ron N

 
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