regulation problems in Aeolian era M and H 50"

[Keith McGavern]

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At 3:34 PM -0500 12/18/04, Piannaman@aol.com wrote:
>Salutations,
>
>I've got some regulation problems on a 50 inch Mason upright from 
>the 70s.  I've worked on other Aeolian uprights of that vintage, and 
>some of them have the same problem.  
>
>The initial problem was that the keys weren't bottoming out on 
>punchings.  It seems that it's been that way since new(though they 
>bought it used).  There was a huge gap between the bottom of the key 
>and the punching when the key was depressed.  This led to hammers 
>blocking, bobbling, and a feel that could only be described as 
>spongy.  

Something is preventing the keys from contacting the front rail 
punchings. Whatever it is, I'd be looking to find out.

>At my last visit, I added punchings, and improved the feel somewhat, 
>but some of the bobbling is still there.  I also had to increase 
>letoff distance in some areas of the keyboard an unacceptable amount 
>to get it to work without hammers blocking against strings.
>
>I think that the main problem is that the key height is too great. 
> It was somewhere around 70mm, though I forgot to write it down. 
> More precise measurements are necessary, and they will be 
>forthcoming after my next visit there in January.  Blow distance is 
>at 1 7/8(the only thing in the piano that seems at spec...:-), but 
>it doesn't seem to be enough.

Taking the measures you is not going to solve the problem.

>I tried lowering the key height on a few sample keys by removing 
>balance rail punchings, but there was nowhere near enough 
>aftertouch.  Should I try increasing blow distance to 2 inches or 
>more?  Any ideas???  Haaalp??

Increasing blow distance is only going to exacerbate the situation. 
Decreasing the distance will enhance aftertouch.

Find the reason for, "... There was a huge gap between the bottom of 
the key and the punching when the key was depressed ...", and all 
will be revealed.

Keith
-- 
Keith McGavern
Registered Piano Technician
Oklahoma Chapter 731
Piano Technicians Guild
USA

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