cracked plate

[pnotnr at aol.com]

 This was just a normal screw type jack.? And maybe this had nothing to do with the plate cracking, but after stringing the piano, it was in a lot tighter then when I first put it in.? I had put it in just snug enough so that I couldn't move it.? I guessed that the string tension pulled that corner of the plate and maybe the jack gave it that borderline amount of support(?)? Probably didn't have the plate in position as well as I thought.

Anyway, the crack happened as I released the jack, so I'm thinking there is some connection.? It's about 5 hours since this happened, and the strings are still at pitch.? 

I don't consider myself a rebuilder.? This project was more of a change of pace for me (I'm primarily a field technician) and this particular instrument was a good one to screw up (if I had to screw up a piano!)? since it had little value to begin with.? I AM feeling gun shy, however.

Gordon Large


 


 

-----Original Message-----
From: Farrell <mfarrel2 at tampabay.rr.com>
To: Pianotech List <pianotech at ptg.org>
Sent: Wed, 2 Apr 2008 3:35 pm
Subject: Re: cracked plate
















What Dale said.


?


Support jack? A pinblock support jack? I'm having trouble 
visualizing how a pinblock support jack could cause the plate to crack. You 
reference "releasing" the jack. What type of jack is it? I'm only familiar with 
screw-type pinblock supports.


?


When you put the pinblock support in place, I guess I've 
never been instructed one way or another, but I just snug it in - I don't jack 
the pinblock up at all. So if the jack didn't move the block, and hence the 
plate, and then you remove the support with tension on the strings, okay, so the 
plate/block will adjust some tiny little bit, but why would it cause a crack? 
Seems to me the plate would be in that position anyway and would be experiencing 
whatever stresses it does either way.


?


I just don't see how removing a pinblock support would 
cause the plate to crack. Thoughts?


?


Terry Farrell



  
----- Original Message ----- 
?Check 
  the Archives for www.Lock-n-Stitch.com. Been lots on 
  it
?Dale Erwin

-----Original Message-----

  
I have a Chickering 1/4 grand 
  in the shop with a hairline crack on the treble strut between the two capo 
  sections.? This is right where a nose bolt passes through, so the crack 
  extends from the top of the strut to about halfway through.? 

I'm 
  sure it was my error that caused the crack.? (I restrung the piano, 
  chipped it, and had it up to pitch before realizing that I still had my 
  support jack in the high treble.? With all the string tension, it was 
  really wedged in.? It was very difficult getting it to release and when I 
  released the jack, I heard the crack.

  
SNIP
Gordon Large, 
  RPT



 

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