Hammers blocking in Seiler uprights

[piannaman at aol.com]

Hello Roger,
 
Suddenly many problems in pianos that I've seen in recent times are starting to make sense.  And I've seen many overeased balance rail holes--I guess "heard" would describe it better than "seen."  
 
Are your findings going to help Bergmans at all...:-)?
 
Thanks for helping the light bulb go on.  
 
Dave 
 
-----Original Message-----
From: Roger Jolly <roger.j at sasktel.net>
To: Pianotech List <pianotech at ptg.org>
Sent: Fri, 07 Apr 2006 23:04:57 -0600
Subject: Re: Hammers blocking in Seiler uprights



Hi Dave,
                    You seem to have a good grasp on what is happening.
To illuminate the picture;   For argument sake. With a 4mm hole the key feels free, travelling through 5 degrees of arc, with a 7mm hole you start to feel resistance at the 3 degree point. and a firmer push is required to push the action through let off and after touch.
The binding makes it difficult to feel let off, and makes even touch almost impossible
 Both Korean manufacturers have tended to over ease the keys to mask the problem. leading to a noisy action, from chucking keys.
After reaming, I have often had to steam the balance rail hole, because the hole had been over eased, masking the hole height problem
Seen the same gross problem in the recent Chinese pianos.
Now for the funny:     I have carried the reaming tool around for about 20yrs, and only used it when I did various balance rail hole repairs.   In the last 12 months I think I have almost wore it out. ;-)  I have hardly used my Yamaha easing tool on any thing but Yamaha pianos.

Regards Roger


 
Thanks for the detailed response.  Very interesting stuff.  I'll have to get a 4mm reamer and try this out.  You've done all of the legwork already!
 
If I'm reading this right, what's happening is the key is not rocking correctly at the pivot point/balance rail due to the overly tall hole, which essentially means the key is acting shorter than it really is...right?  And manufacturers have counteracted this by increasing dip to 11mm...?  
 
I think I'll buy a Seiler just to experiment with in my garage....:-)
 
Thanks again!  Your generosity is always appreciated!
 
Dave 
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