Upright pinblock question

John Ross jrpiano at win.eastlink.ca
Sun Oct 28 00:24:54 MDT 2007


Talking of a big bang. One tech told me, when a plate broke on him, a piece of the plate, went through his pant leg. Luckily, he had loose pants on, as it would have made short work of his leg.
That is the story, he told me, even although, I found it hard to believe, that it didn't get his leg.
John M. Ross
Windsor, Nova Scotia, Canada
jrpiano at win.eastlink.ca
  ----- Original Message ----- 
  From: Willem Blees 
  To: pianotech at ptg.org 
  Sent: Sunday, October 28, 2007 12:58 AM
  Subject: Re: Upright pinblock question


  Terry

  This is a classic example of the pin block separating from the back frame of the piano. This might be one of the reasons the piano was 140 cents flat. My advice is not to wait until the problem gets worse. This needs to be repaired as soon as possible, or else, as Terry described, the owners will hear a big bang in the middle of the night, if they are lucky. The plate could also collapse when there are people in the room, and it will not be a pretty picture. 

  There is only one proper way to fix this, especially with a crack as big as you have, going all the way from the bass to the treble. Take the tension off the whole piano. Remove the plate screws at the top of the plate. Drill holes all the way through to the back of the piano. Insert 4", (or what ever the distance is from the front to the back of the piano), stove bolts, and tighten with washers and nuts. (The nuts are on the back of the piano). Then take 4 or 5 C clamps, or pipe clams, or what ever clamps you can get a hold of, and start tightening them as much as possible. With each turn of the crack, tighten the nuts. Keep doing this until the gap is closed. No need to put any kind of glue in the crack, because the glue is not what is going to keep the frame and the pin block together. 

  Keep doing this until the crack is gone, and the nuts are tights. Then you can remove the clamps and tune the piano. This is a big job that will take several hours. But it will be cheaper than a new piano, and much cheaper than the medical bills after the explosion. 



  Willem (Wim) Blees, RPT
  Piano Tuner/Technician
  Honolulu, HI
  Author of 
  The Business of Piano Tuning
  available from Potter Press
  www.pianotuning.com


  -----Original Message-----
  From: pianolover 88 <pianolover88 at hotmail.com>
  To: PIANOTECH at PTG.ORG <pianotech at ptg.org>
  Sent: Sat, 27 Oct 2007 4:07 pm
  Subject: Upright pinblock question


  Recently acquired an amazingly well preserved Kohler & Campbell art case console made in 1969. To look at it, you would think that it could have been made yesterday!  It has never been played, thus the hammers are unmarked after almost 40 years! Even the wooden wedge was still screwed in securing the big panel (some call it the kick panel?) above the pedals! 

  Anyway, the pitch was (not surprisingly) grossly flat--close to 140 cents at A4! I checked all the plate bolts and they were 90% snug, needing maybe 1/8 turn to totally snug them back down. The tuning pins were found to be all uniformly tight, and responded beautifully to minute, incremental adjustments. The pitch came right up to A440 after the first pass, and after letting it settle for a while I gave it its first tuning in nearly four decades. 

  I followed that with two more fine tunings to make it as solid as possible for the time being. Ok, now to get to the main reason for my post; There is, what appears to be a separation, not really a crack but a perfectly clean separation at least 2-3' behind  the pinblock laminations, that runs the entire width of the pinblock. 

  As I stated the pins are uniformly tight, the laminations sound, and the plate bolts tight. Also, I wanted to know the depth of the separation, which ranges from maybe 1/2-1 millimeter wide at the very most, so I used a very thin piece of steel and found that it was only about 1/4'-1/2' deep. Should this flaw be cause for concern, or is it likely not going to affect the stability? The tuning seems to be holding, but then I just finished it maybe an hour ago so... 

  Would it maybe help to 'fill' this crevice with thin west systems epoxy, until it fills the area, then just let it dry and move on, or would that just be a waste of time and epoxy? Or maybe Gap filling CA? Of course, it would take quite a of CA to fill a 56' long, 1/2' deep cevice! Thoughts and advice would be appreciated! 

  PS: See the pics.

  Terry Peterson

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