Upright pinblock question

[John Ross]

I use 6 eight inch C clamps.
I do it before bringing to pitch. Sometimes it will come up in pitch, quite a bit with the clamps.

Mind you, I like Terry's idea of monitoring, to see if there is a drop in pitch, before doing anything, because it is such a small separation.

The C clamps could be put in place, to act as insurance, that it wouldn't suddenly come apart and break the plate.
I remember when a plate broke on me, the first time I ran into the problem, back in the 70's. I couldn't see the pinblock, as the top cover was split, and glued down over the top, with a hinge in the middle.
I couldn't figure out why the piano kept dropping in pitch, as I brought it up to pitch.
Then there was a big bang, and the top of the plate came forward 6". I nearly had a kitten.
Since then, if a large pitch raise is required, I always, make sure that I can see the top of the pinblock to make sure there is no separation.

John M. Ross
Windsor, Nova Scotia, Canada
jrpiano at win.eastlink.ca
  ----- Original Message ----- 
  From: pianolover 88 
  To: Pianotech List 
  Sent: Saturday, October 27, 2007 11:56 PM
  Subject: RE: Upright pinblock question


  Thanks for the tip! But it's gonna take some big-ass clamps! Will C-clamps work?" How many should I use and how far apart from each other? I figure those big wooden clamps wont give me the pressure necessary to close the gap; if it *is* able to even close.

  Terry Peterson



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    Date: Sat, 27 Oct 2007 23:44:28 -0300
    From: jrpiano at win.eastlink.ca
    Subject: Re: Upright pinblock question
    To: pianotech at ptg.org


    See if you can close the gap with clamps.
    If you can, then it needs bolts through to the back for stability.
    If you can't close the gap, then you would probably be ok with epoxy.
    John M. Ross
    Windsor, Nova Scotia, Canada
    jrpiano at win.eastlink.ca
      ----- Original Message ----- 
      From: pianolover 88 
      To: PIANOTECH at PTG.ORG 
      Sent: Saturday, October 27, 2007 11:07 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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