[pianotech] Brands prone to breaking plates

[John Ross]

The plate that broke for me, was due to pinblock separation.
I was just new in the business, only instruction, an inferior correspondence course.
In the 70's tuners around here would not help as they were thinking you would be their competition. 
I hadn't joined the Guild, or started going to conventions, so my knowledge was minimal.
The piano was away down in pitch. Now I would look for the signs of the separation, as indicated in previous posts.
The strings were vibrating against the plate on hard playing. 
I, naively thought, that when I brought it up to pitch, it would push the soundboard and strings away from the plate. 
It kept on slipping back in pitch as I was taking it up, and suddenly, BANG. I nearly had a heart attack, my heart beat went away up.
Now I check if the pitch is down a large amount, and inform the customer of the possibilities.
Another tuner told me a plate broke on him, and a piece of the plate went through his pant leg. If it had been a little closer, it would have shattered his leg.
John Ross
Windsor, Nova Scotia
                  
  ----- Original Message ----- 
  From: Andrew Remillard 
  To: pianotech at ptg.org 
  Sent: Friday, April 17, 2009 5:42 PM
  Subject: Re: [pianotech] Brands prone to breaking plates



  Back to the list. 

  J. Bauer open face  1910's
  Bechstein same period
  Weber 11910's open face

  I am starting to see a pattern here. I have found four different type of harp breaks. The open face harps tend to have too little iron through the pin field and fail often across what little strut material they have.

  Struts often break because of poor factory setting, improper "rebuilding", and tooners who have strange notions about using nose bolts to adjust voicing. (I am not making this up!)

  Pin field failure. Since the stress here shouldn't be that severe I would imagine most are caused by casting problems or a very poorly fit pin block which led to more pressure on the harp from the tuning pins than should have been present.

  And the finale one is the treble hitch pin field breaking off. This tends to be the loudest and most frightening. I had this happen once while tuning a spinet. I had just pulled my head up from looking at something under the key bed when it happened. As others have said, it does get your attention.
  -- 
  Andrew Remillard
  ANRPiano.com
  2211 Curtiss St.
  Downers Grove, IL  60515
  630-852-5058
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