[CAUT] Steinway stack height

[Wolfley, Eric (wolfleel)]

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Thanks Chris and all that replied. I'll thumbtack the specs to the wall so I
won't misplace them. I did contact Kent Webb and the current spread
specification is 4 13/32" which translates to 4.40625"

 

The piano in question is indeed of 1968 vintage (Mr. Purdy) and was
originally Teflon with the big fiber knuckles. I isolated the problem to two
sources: The rear of the stack was 1/16" too high (3 5/16")...easy enough, I
carefully planed the shoes down. The shank bumpers on the new wippens I want
to use (Tokiwa miracle wipps) are 1/8" higher than the original. We save a
lot of old parts here...it was good to have some samples to check. This
piano had a new soundboard installed a few years ago (before I started here)
and obviously the string heights are lower now than its original
incarnation. 

 

In Chris's post below I can't exactly visualize what they are talking about
when they say "continually check for straightness with the straightedge on
top of the hammershank flanges". My only guess is that if the mounting
blocks aren't all on the same plane the hammer rail could warp down or up
where a stack bracket is screwed down but it seems like it would have to be
really bad for this to happen.

 

 

 

Eric Wolfley, RPT

Supervising Piano Technician

College-Conservatory of Music

University of Cincinnati

 

-----Original Message-----
From: Chris Solliday [mailto:solliday@ptd.net] 
Sent: Monday, July 18, 2005 5:07 PM
To: College and University Technicians
Subject: Re: [CAUT] Steinway stack height

 

"B" at note 62 in NYC hammer flange 5 3/4"

rep flange 3 1/4"  based on string height of 7 1/2"    you didn't say if pre
84 or post or the new incarnation but the spread pre 84 was  4.381" and post
84 was 4.395"  This may have changed on the latest and greatest and for that
I suggest you call Kent Webb or email him.  I think it is important to note
that according to Mike Mohr's Forefinishing Notes, which I consider a
reliable source, "Set Action Frame Height" says "IMPORTANT NOTE: the action
stack height, as determined by the thickness of the mounting blocks. This
action height is unique for each instrument, and is the result of the
individual string height for a piano. String height variables are the result
of the plate fitting and belly operations... String heights change from bass
to treble usually in an arched or crowned manner. These numbers for note #
62 represent an average. Maintaining the relationship between the stack
height and the string height ensures: A) the proper BLOW distance at the
same time the hammershank is properly off the cushion. and B) the proper
HAMMER ROTATION is needed to minimize overstriking or shallow striking
conditon. NOTE; if string height is lower or higher than above, keep the
relationship the same..." (and later after shimming or planing the bass and
treble mounting blocks) "continually check for straightness with the
straightedge on top of the hammershank flanges." I know you only asked for
numbers, but what the heck, I felt like sharing. BTW I'm sure you remember
that we discovered when shimming or planning it is best to rotate the stack
on the hammer flange pin axis which means adjusting the front foot
differently than the back foot. Of course there are even greater subtleties
to this process but then you did just ask for the numbers. Stay well, Chris
Solliday  

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

From: Wolfley, <mailto:WOLFLEEL@UCMAIL.UC.EDU>  Eric (wolfleel) 

To: 'caut@ptg.org' <mailto:'caut@ptg.org'>  

Sent: Tuesday, July 19, 2005 9:53 AM

Subject: [CAUT] Steinway stack height

 

Hi All,

 

I'm sure somebody out there knows the specs for the distance from the keybed
to hammerflange center and keybed to wippen center for a Steinway B. I have
these written down somewhere but can't find them and I don't trust my
memory. I'm correcting a problematic action and believe the stack to be too
high since to get the proper blow distance the shank cushions have been
reduced to nubs. The bore distance of the hammers is correct and the string
heights are in the normal range.

 

Thanks!

 

Eric Wolfley, RPT

Supervising Piano Technician

College-Conservatory of Music

University of Cincinnati

 


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