Hammers blocking in Seiler uprights

[Roger Jolly]

Hi Pianoman,
                           You may have several issues working 
against you.    I have just finished do some research for SMC on 
vertical pianos that had similar problems,   The general consensus 
was that there was a geometry problem..

After checking all kinds of parameters the solution ended up being very simple.

The Balance rail hole was way too tall. ( 7mm on some models.)  Ream 
the B/R hole down to 4mm and reduce the dip from 11mm to 10mm.  The 
problem pianos play beautifully.

If the hole is too tall, the pin starts to bind in the hole making 
let off and after touch very ill defined.  This will be very 
noticeable on ppp playing.

Balance rail hole height, dip, F/R cloth punching, and after touch 
are all interactive.

 From empirical data from 1000's of keys measured, I have come to the 
following conclusion.
A spruce key needs only 4MM of key height,  Maple shoe keys 3mm height.
The only manufacturer  that I have found to be consistently correct 
has been the Yamaha Corp.
Samick after last August key production, has been corrected, and a 
separate QC check is in place to monitor the measurement.

This single measurement is probably the most critical of all 
measurements in how any action feels. It also has a dramatic effect 
on note to note consistency if the mortice is poorly machined.

On the manufacturing side,  rate of feed, frequency of changing the 
router bits, chip out cleaning etc.  All have an effect on the 
quality of the mortice.

The only visible problem.      mmmmmmmmmmmm     Your quote:  The hole 
height is hidden in the bottom of the mortice. ;-)

The reaming tool is available from Pianotech,  or Jurgen

Keep your finger firmly on the bottom of the hole and ream away until 
the tip touches your finger.  It only takes 30min to do a key board.


Hope this helps
roger


At 12:22 AM 4/7/2006, you wrote:
>Hi List,
>
>I took a breather from the list because business has been pretty 
>good, and wht do I see in my mailbox?  637 messages from 
>pianotech...  Wish I'd had the time to read them all!
>
>I have recently encountered an interesting problem in a few Seiler 
>uprights.  Last week it was in a 132, probably 2 years old.  This 
>week it was a 122, similar vintage.  Both were purchased as new from 
>a dealer within the last 7-8 months.  I've also seen this problem 
>with a few Seilers of slightly older vintage.
>
>What's happening is that the backchecks are checking the hammers a 
>bit too close--like right into the string, if you push on the key a 
>tad, or on a soft blow where the hammer rebounds slowly and gets 
>smushed into the string by the backcheck.
>
>There is adequate lost motion.  In one of them, there was negative 
>lost motion, but the problem persisted after regulation of lm
>Let off is good, right around 3-4mm
>
>The only VISIBLE problem is the checks are regulated way too close.
>
>After making the the lost motion was okay, I regulated so checking 
>around 10 mm.  It works fine.  It's strikes me as odd that this 
>would happen, because they weren't that way at the first 
>tunings.  Granted, we are having a wet winter, but I can't fathom 
>how humidity could cause this. They are both in relatively stable environments.
>
>About 4 years ago, I dealt with a Seiler that had this, and many 
>other regulation problems seemingly caused by environment.  AFter 
>regulation, the piano has been quite stable.
>
>Anybody with similar experiences with these pianos?
>
>Have a great weekend,
>
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