Plate Flexing

[David Love]

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While taking off the plate bolts of a Steinway L (c1961) I noticed the
plate coming up at the tail.  The photo shows a stretched string between
the agraffe and hitch at note 27 after removal of the bolts--no movement
in the treble, btw.  Before removing the plate bolts, the bearing
measured plus 1o at this point.  Total amount of flex in the tail was
about .75".  Interesting in that the bridge is fairly uniform height and
the plate is level along the stretcher.  If I were to recap the bridge
to accommodate the plate in a neutral position, there would be a 14 mm
difference between the height of the bridge at not 27 and note 88.  

While the plate clearly has sat this way for a long time, I'm not real
crazy about bending it that much again.  Plate flexing on Steinways is
common but I've always wondered what the upper limit is.  This seems a
bit excessive.  This piano will not get a new soundboard (unfortunately)
but that wouldn't really solve the problem anyway.  It seems that the
plate is warped.  The string height does dip somewhat at the top of the
treble (typical) and since I'm putting in a new block my thought is to
raise that side of the plate a bit which would rock the plate down a bit
in the back (though not much), recap the bridges (all of them will need
to be done) to allow a lesser amount of flexing at the tail.  

Any other suggestions or comments would be welcome.  

David Love
davidlovepianos@comcast.net 

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