Steinway key humping

[Robin Hufford]

I have access to a number of Steinway grands but will answer this without
checking them directly as they are at another location.
     The crowning of the keybed occurs in a very small strip which runs across
the keybed under the corresponding strip planed in the front rail and does not
involve the rest of the keybed, nor, does it involve the other rails,  I
believe.  Convexity meets corresponding concavity as  the screws pulling down
the check blocks insure through their action on the keyframe pins that the two
stay together, or should so through the pinching action of the screws on the
pins.   I believe the aim of this is to ensure a more reliable contact.
Personally, I doubt it is any better than the system used by Chickering  as, in
my experience, Chickering's system doen't  need as much bedding of the keyframe
as one encounters on old Steinways.  The Chickering system,  which relied on
flat rails on a flat keybed, no keyframe glides and a different rail and stile
system than that used by Steinway, is, in my experience rather better.  Until
the twenties, the keybed used on Chickering was comprised of a two notched,
parallel rails running transversely to the length of the piano,  under the area
of the keyframe rails.  Into these parallel rails were laid panels which are not
glued in and are free to expand and move left or right much like a technique
used in certain furniture construction.    Steinway relies on a glued up
keybed.
     The question of crowning the plane of the key height is an entirely
separate matter - designed, as has been pointed out, to ensure that the heavily
played, central area of the keyboard does not develop, after heavy use, a
sagging curve as can be seen to have happened on some pianos, and, I think,
would have to be considered to be independent of the question of crowning the
keybed itself or not.
Regards, Robin Hufford

Carl Meyer wrote:

> Yes, I forgot to mention that S&S rep also said it was to assure full
> contact of the key bed with the bed.  A curve in the frame would have been
> sufficient, I think, but curving both really complicates matters.
>
> Ron asked if the rear was also crowned.  I don't know, but since I   clamp
> at both ends  at the front and three places at the rear it doesn't matter.
>
> Any one who has access to a  few S&S grands, would you check with a straight
> edge front and rear and let us know.  Thanks.
>
> I'm sending you privately some pictures of the leveler.
>
> Carl Meyer Ptg assoc
> Santa Clara, Ca.
>
> ----- Original Message -----
> From: "Michael Gamble" <michael@gambles.fsnet.co.uk>
> To: <pianotech@ptg.org>
> Sent: Monday, October 20, 2003 7:24 AM
> Subject: Fw: Steinway key humping
>
> > Hello Carl Meyer
> > Even as I read your comments and approached your conclusions I was saying
> to
> > myself "If the keybed is crowned, surely by simply leveling on a good flat
> > surface the result will be the same as levelling when clamped down to the
> > S&S keybed"? And then you answered it with just that same observation.
> > What is your "Key Levelling System" Carl?
> > Regards
> > Michael G (UK)
> > ----- Original Message -----
> > From: "Carl Meyer" <cmpiano@comcast.net>
> > To: <pianotech@ptg.org>
> > Sent: Monday, October 20, 2003 1:57 AM
> > Subject: Steinway key humping
> >
> >
> > > I've commented on this before, but some may not have noticed or disagree
> > > with me.
> > >
> > > Since I am the self appointed key leveling guru, I need to reiterate
> that
> > I
> > > believe the idea of the 1/16 hump in the key leveling of S&S has been
> > > misconstrued.  Setting a hump in the keyboard for the purpose of
> > > compensating for the  sagging due to the excessive playing of the center
> > is
> > > just urban legend.
> > >
> > > I recall when I first heard that, I was impressed with that concept.  I
> > have
> > > been now convinced that to misadjust to compensate for wear is not a
> > logical
> > > engineering decision.
> > >
> > > An S&S rep told me that the reason for humping the key leveling is to
> > > compensate for the fact that they shape the key bed for a level of crown
> > of
> > > about 1/16 inch during manufacturing.  The key level then should follow
> > the
> > > curvature of the key bed.  This requires the key frame to be clamped by
> > the
> > > cheek blocks for the purpose of having better contact due to the
> curvature
> > > of the key frame.  I was then told that it was necessary to level (sic)
> > the
> > > keys in the piano since that would be the only way it would be accurate.
> > >
> > > I still hold to my concept that if you clamp the action (key frame to a
> > flat
> > > table) and LEVEL the keys, when you reinstall the action the hump will
> > > automatically the same as the key bed.  Isn't that what they want?  Any
> > > additional leveling to what ever shape you want or touch up can be done
> > > after the action is in the piano.  You may drive yourself to utter
> > > frustration or terminal if you like.
> > >
> > > I know of no other piano manufacturer who purposely makes their key beds
> > > unleveled. I was even told by another S&S rep that the key bed was
> > stronger
> > > because of the (crown).  Can any of you math gurus tell me how much
> extra
> > > strength 1/16 crown over 4 feet of a 1 1/2  thick key bed will produce?
> > >
> > > Just look at all the consternation this one item has caused.  How many
> > > e-mails have been written.  Gives all the S&S apologists a reason for
> > being.
> > > Argggggggg!!!!!!  Could any other manufacturer  do something like this
> and
> > > not been blasted?
> > >
> > > By the way, Joe Goss is now selling my key leveling system.
> > >
> > > Carl Meyer Ptg assoc
> > > Santa Clara, Ca.
> > >
> > >
> > >
> > >
> > > _______________________________________________
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> > >
> >
> >
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